I have played both Alliance and Horde in the past 4-ish years I have been on Warcraft. Ally side I cannot say there is a race I like to play. I usually picked Night Elves in the past but I didnt really click with them and I hate the male model and position in Nelf society. If I had to create another Ally I would choose a Worgen.
Horde side I like all the races. I have had quite a few Taurens and my alt Hunter is a Troll. My new love is the Goblins. Autumnn has always been an engineer and the fact Gobbies are tinkerers is very appealing. I also like their small size. Being a Tauren I had to dismount to get through doors and running some instances like Shadowfang Keep were problems with the Taurens large size. I like how Goblins can get through anything and should always be expected to have a bomb in hand.