Guys quit bringing the stormcloak-imperial issue into this, this is about races not what what the races represent or fight for.
as for me I've played Arena, Daggerfall, Morrowind, Oblivion and Skyrim, so needless to say i know the elder scrolls universe like the back of my hand. My favorite races are the Bretons and the Khajiit.
I like the Bretons because of there versitility as assasins or mages and their Nede-Aldmer pedigree. and just for the record, Nedes and Nords are the same thing, Nede was just the name of the first Nords that came from Atmora before being killed by the falmer and then returning with Ysgramor as the Nords, so no they were not short. anyways the bretons are interesting because they have had to deal with being conquered 5 times. and not only have they survived but they have thrived. that makes them a solid candidate for best race.
The Khajiit, while in game being really only good as thieves, outside the game are the most versatile race in Tamriel. The Khajiit in Morrowind, Oblivion and Skyrim are of the Suthay-Raht breed, while the Khajiit in arena and Daggerfall are of the Ohmes breed, which has no fur and is similar in appearance to the Bosmer of Valenwood. What the hell am I talking about you ask? well if you know about Khajiit you know that their form is determined by the phase of Nirn's moons, Masser and Secunda. Which can range from the elf like Ohme, the short furry far more cat like Suthay and Suthay-Raht to the tall muscular felines the Cathay and Cathay-Raht. this is not even mention the more exotic breeds of Khajiit, which are are more similar to house cats or lions.