I know:

--Nords are based off of Vikings, and their culture as well, even the Religion.
--Imperials are based off of Romans.

The rest are based off what Tolkien started.

Zing!
In part, and most obviously, yes.

Although the "Elf" that we all know and love is very much a Tolkienesque creation, Elves themselves first appear in Germanic and Scandinavian folklore.
The term Elf is also often used to encompass all manner of faeries (or fairies), literally "Fair" or "Fey" folk from both what is known as the "Seely" and the "Unseely" court - two opposing - (in a sense) - factions consisting of all sorts of sprites and goblins and other creatures.
Elves themselves assumed a far more supernatural role as time went by, being depicted very much as nature spirits, living in woods and under rocks, often of a very diminutive size.
(Interestingly Spriggans fulfil an Elf-like nature spirit role).
It was 19th Century romantic literature that brought elves back to full size and started the evolution of the look that we know today. All Tolkien really did was take this 19th century evolution and further develop it, along with some rudimentary splits in elf factions and types and further developing Orcs - (corrupted elves, a concept taken on by pretty much everyone since) - and Goblins, which are themselves still anologues of the perhaps more "unseely" aspects of faerie lore.
based upon Tolkien, the idea of Elves as Dark, Wood, Snow, etc... was further developed over time to give us what we have now. Their rise to prominence is largely due to Tolkien and before him romantic poets, authors and artists. But their roots are far earlier.

In truth, an "Elf" pre-19th century would be a lot closer in appearance to Dobby the House Elf in Harry Potter, but might appear to humans in a glamour as something more akin to Legolas or Eowyn...

Redguards seem to be based off egyptians or from around there.

North african moors mostly.

The Bretons are a mix of anglo-french for the most part.

Don't forget that Tolkien took all of his lore from pre-Christian Norse, Germanic, and Celtic mythology. Gandalf and Aragorn are right out of King Arthur. So while TES owes a lot to Tolkien, Tolkien is just the man who brought all of this mythology back into the modern literary consciousnesses.

God. I love you both.

I get so sick of people always chirping about how Tolkien created this and that, and I always point out the Fae folk and they just pretend that folklore never existed.

I have only one argument to this. Eowyn was human. You meant Arwen, perhaps?

This is my theory:

Nords - Vikings
Imperials - Romans
Bretons - Celtic
Redguard - North African
Kajhiit - Asian / Arabic
Orcs - Mongolians
Altmer/Dunmer - based on Norse/Germanic mythology (not sure what their culture is based on though)
Argonians - ?

argonians-spider man duh the lizardman

I'd say kajhiit are closer to the Arabic side of things, middle east area.

Bretons strike me as French.

I believe the Kajhiit are closer to Arabs as well, but since Elsweyr has jungles, I included Asia (east Asia) as well. If I'm not entirely wrong, the Arabs did occupy northern India, so maybe that makes up for the jungle part....

And France was a part of the celtic regions: http://en.wikipedia.org/wiki/Celts

The French were Celts, if you go back before Gaul was conquered by the Imperials Romans.

perhaps the Turks, I believe their empire was in that region for a time

also, with Bretons I was just narrowing it a bit ... celts were a mish mash of things

Not every race needs to have a direct real world correlation.

The Nords are not just Norse. When you look deeper, you see Egyptian influence, particularly in their ancient culture. The ancient Nords would mummify their dead. They also take religious influence from Hindusim, with kalpas being the most obvious. Don't think they're TES Vikings.

Argonians have a rather Native American tinge to them, IMO (which takes on an interesting angle when you consider the Hist to be the true natives of Tamriel, or all of Nirn for that matter). Like all TES races there's no direct correlation, there are differences, but there is usually a solid base from which they're derived.

Yeah I meant Arwen - (the other cute one)

I always though Kahjiit were based on gypsies. Which are pretty much Spanish. Which are a mixture of everything in Europe.

Imperials - Roman
Nords - Vikings
Redguard - Moors (North Africa)
Bosmer - Native American if anything, but its very loose
Altmer - Ancient China
Dunmer - Japan, but again very loose
Orsimer - Mongolia, especially Mongol Hordes
Bretons - Bretons (from Brittany in Northern France)
Khajiit - Middle East
Argonians - Not really anything, perhaps places like Vietnam, Laos etc.

But again, aside from perhaps Imperial/Roman, these are all different from their real life counterparts. It's less like the devs went "Hmmm.... who can we base the Redguards off...the Moors!" and more that they gave each race a distinct personality that in some ways mirrors the personality of some places in history.

I'd say it's still mostly Norse. Sure, there are obvious differences between Vikings and Nords, but I'd say that they are very similar to a great extent. Jarls, housecarls, horned helmets (which Vikings didn't really have, but the popular image says so at least), Sovngard/Asgard, dragons, the way the boats look, draugr (they are a part of Norse mythology), mostly norse names among nords, Skyrim being in the north (like Scandinavia is referred to as the "Nordic countries"), the environment being similar to Scandinavia, and so on...

I could make a huge list of the similarities, but I don't have the energy right now.

In other words: Sure, the nords are not 100% vikings (obviously), but they are heavily similar with vikings.

The Gypsies, or Roma as they call themselves, hail from Northern India and are most often associated with Eastern Europe.
Just FYI, the term 'Moor' is generally seen as pejorative nowadays.

Really? I didn't know that, I figured it was just more of an archaic way to refer to North Africans. I'm using it to refer to a historical time period, around the time when they invaded Spain.

No doubt. But it's boring and somewhat misleading to call them Norse.

Yeah I hear ya. That was four semesters of Anthropology talking. It's really only considered an insult in Southern Europe where you find large populations of North African immigrants. Ironically, the Inquisition had expelled all the Moors by 1492, now they live in Europe in greater numbers than they ever did as invaders.