If you have information to add, please let me know

*Credit: Awaiting confirmation, Tarantula Keeping Community, The World Spider Catalog by Norman I. Platnick.

This list is for better understanding the similarities, differences, and distribution of a broad range of tarantulas. It is by no means complete in terms of information provided.

The Subfamilies:

Acanthopelminae
Aviculariinae
Eumenophorinae
Harpactirinae
Ischnocolinae
Ornithoctoninae
Poecilotheriinae*
Selenocosmiinae
Selenogyrinae
Spelopeminae*
Stromatopelminae
Theraphosinae
Thrigmopoeinae

Subfamily: Acanthopelminae
South and Central American terrestrial tarantulas.

Subfamily: Aviculariinae
Avicularia means "small bird" in Latin due to an early misconception about a tarantula's preferred diet, but it may as well mean "flat-footed-spider-with-something-odd-about-its-urticating-hair" due to the characteristics of some members of this subfamily.
For example, take the members of the Avicularia genus: They are tropical arboreal spiders common from the Caribbean to South America and many are commonly sold as "pinktoes," no matter what species they are. Some, such as Avicularia avicularia, can tolerate each other in a group setting if given enough space, but will kill each other on occasion if there's not enough room or food. They're fairly docile, but can move quickly if need be. What's really special about most of them and the genera Iridopelma and Pachistopelma is that not only are they the only arboreals with urticating hair, they can't "flick" the hair to make it float off into the air. The type of urticating bristles they possess (Type II) must be pressed into its intended target (A. versicolor may differ).
Also included are the bizzarre Ephebopus tarantulas. They have flattened "feet" like arboreal spiders, yet prefer to dig burrows. Those "platypus" tarantulas are the only known genus with urticating hair on their pedipalps.
Some taxonomists include members of the genera Psalmopoeus and Tapinauchenius, which have no urticating hair, in this subfamily; along with some members of Holothele, they are some of the few New World tarantulas that lack that trait.
What's really confusing is that many of the described species of the Avicularia genus are probably invalid. There are descriptions based on cast exoskeletons acquired from a "friend of a friend," descriptions of only one gender, descriptions without locality data (except to say they came from a friend's pet collection- in some cases, that's where the species name is derived), descriptions with no examinations of other holotypes in the genus, etc. Unfortunately, systematics for theraphosids isn't a scrutinized, regulated thing. Snippets from a fanzine-style journal published without peer review is enough to get a "species" listed in the World Spider Catalog. This is fun, exciting, and sometimes profitable for pet traders, but quite unfortunate for those wishing to understand faunal relationships and environmental impacts within ecosystems. Questionable species are marked with an asterisk.

Subfamily: Eumenophorinae
These are the big African "baboon" spiders. They are normally very defensive and most like to dig deep burrows. The majority of the members of this subfamily require a good amount of humidity.

Subfamily: Harpactirinae
These are also African "baboon" spiders. Though smaller, they have unique habits and are still very defensive on the whole; species of Pterinochilus will rear up upon the slightest disturbance. Some members of this subfamily will often stridulate. Most are burrowers of dry scrubland habitat, but members of Pterinochilus sometimes show semi-arboreal tendencies.
In 2002, Richard Gallon made major revisions to this subfamily, including the removal of the genus Brachionopus to another family of mygalomorph spiders entirely.

Subfamily: Ischnocolinae
This is the most widely dispersed subfamily of theraphosidae. Some species are native to the Middle East, some to Asia, others to Southern Europe, and still more to the Americas. For now, notice the global distribution of eighty separate species (there's one near you!) of which the habits are little understood. Also, what is the relationship of all the members of such a widespread subfamily?! What is/are the determining factor(s)? Why do so many species move in and out of here on a yearly basis?
Clearly, this subfamily is a testament to how little we know about tarantulas.

Genus: Proshapalopus
I've put this in its own genus category separate from the Ischnocolinae table due to the fact that I think I'll end up moving it soon. It seems that the subfamily Ischnocolonae continues to be a foster home in systematics. Cyclosternum used to be in this subfamily, as did Thrixopelma and a host of others. Recently (as of 2001), spiders have been reclassified out of Theraphosinae (Pamphobeteus in specific) into this one. However, this genus was listed as being in synonymy with Holothele by Raven in 1985 and that synonymy was recognized by Platnick, but recent efforts by other arachnologists has changed that. It seems there is little agreement in taxonomyland, and that is to be expected- classifiying such a mysterious animal must be difficult.

Subfamily: Ornithoctoninae
These are tarantulas revered for their colorations and defensiveness. Most are native to southeastern Asia, enjoy high humidity, and have a striped pattern on the opisthosoma.
Most are of quite similar external appearance and some species may be removed sooner than later (and plenty more new discoveries added) by Volker von Wirth once he completes his research on this subfamily.

Subfamily: Poecilotheriinae
These are the Indian "tree spiders" native to India and Sri Lanka.
Their habitat in southern India and Sri Lanka is rapidly dwindling due to deforestation. They were under consideration for inclusion to CITES (Convention on International Trade in Endangered Species) in a proposal sponsored by the United States and Sri Lanka, but that proposal was rejected in April, 2000. If they are included in CITES, they can't be exported, yet where they live will likely be destroyed (at least in the case of India). Some scientists estimated that some Poecilotheria spp. would be extinct by 2005 if human expansion into their habitat continued at its present rate (Charpentier 1996). It hasn't happened yet, but, in the seconds it took you to read that, another tree full of Poecilotheria just went down. For that reason, all are on the "red list", as captive breeding of this genus needs to be a top priority!

Subfamily: Selenocosmiinae
Eastern hemisphere tarantulas, including some Australian ones. Some are profuse web dwellers and many enjoy burrowing.
Others, such as Poecilotheria and Psalmopoeus, are arboreal.

Genera:Psalmopoeus and Tapinauchenius
These genera are unique in terms of their relationship to other Theraphosidae. They stridulate via structures somewhat similar to that of the Selenocosmiinae, yet they are native to the Americas. Unlike other genera of Aviculariinae, they have no urticating bristles. Some taxonomists assert that they are an evolutionary relative of the Selenocosmiinae, like Poecilotheria (Pocock 1899). In captivity, I've observed the mating behavior of P. irminia to be more reminiscent of P. regalis than A. avicularia, and have seen both males and females of P. regalis make drumming overtures to P. irminia, which responded in kind!
However, the mature males do have spurs (much like those of Ephebopus spp.); Poecilotheria and the Selenocosmiinae do not. Like other members of Aviculariinae, the male's emboli are simple in both Psalmopoeus and Tapinauchenius. Those of Poecilotheria are more complex. Ontogenetically, the color pattern development of young Tapinauchenius (and to some extent, Psalmopoeus) reinforce their long-term evolution in their niche, in similar fashion to Aviculariinae.
Truly, these genera are a testament to scientific hypotheses about biological evolution- there doesn't see to be an agreeable home for them right now, but figuring out where they fit in an evolutionary fashion could be revealing about more than just the spiders themselves. Their placement is an important consideration, as it could provide clues as to how other animals are evolving, and how our planet is changing.

Subfamily: Selenogyrinae
Indian and African tarantulas.

Subfamily: Spelopelminae
See the genus Hemirrhagus under subfamily Theraphosinae

Subfamily: Stromatopelminae
West African Arboreals. Philip Charpentier's travels to Africa and persistent work have greatly clarified mysteries about the life cycles and habitats of these species. Of great interest is their evolutionary relationship with the Eumenphorinae.

Subfamily: Theraphosinae

Subfamily: Thrigmopoeinae
Indian Tarantulas.