About choosing your race:
If you are NOT a min-maxer then it doesn't matter, because you will likely more enjoy your game play if you simply chose the race based on your aesthetic affinities.
If you ARE a min-maxer then there is a lot more to consider then simply looking at racials...
For start, every race has different base attributes, and different attributes benefit certain classes more (table below):

Of course you will also look at your racials, but you should consider skill bonuses WAY more important then actual racial spells (that most people prioritize). Examples are Trolls +5 to bows or human +5 to swords/maces.
This is important in the endgame, when your weapon skill determines how often you will miss (important for fighting raid bosses), and +5 from your racial can mean that instead of 2-3 items of your gear with "+hit" on it, you can equip items with crit (or something else) instead that can then increase your raid DPS or tanking effectiveness (observe table below):

For example, as an orc hunter (300 bow skill) you need 9% hit on your gear to be hit capped (to get maximum DPS, and so that your tranq shots do not miss) while troll hunter with a bow will have 305 (due to racial bonus) and only need 6% hit to be capped. That means he will be able to have 3 gear items with crit more than an orc hunter, while still being hit capped.
This is valid for other classes, and other weapons as well.
There are also other factors to consider, some examples are Taurens bigger hit box window, or Gnomes low height preventing them being targeted by damage (but also healed) due to LOS issues, at same spots where higher races would not have this issue.
As a min-maxer there is LOT more to consider then simply looking at racials, so for a good answer at what race is best for you you should actually do some decent research yourself, and not trust most answers given to you on web by noobs (that think they are smart) who only look at part of this factors (hell, most of them are looking racial skills only)...
Hope this helped. 