Imperials.
In terms of combat, Imperials are best equipped for the warrior type. Based on their bonuses, with +5 to Blade, Blunt and Hand to Hand, they can pretty much take their pick from weapons and craft a front-line warrior, and their +10 in heavy armor provides them with ample durability.
With their extremely high personality stat, as well as +10 to Mercantile and Speechcraft, Imperials are well suited to haggling and negotiating, and generally have no trouble getting others to like them. If you wish to explore a more roleplaying-oriented, less combat-focused character, an Imperial is a good choice, as their abilities can lend themselves well to a less violent lifestyle.
Imperials are one of the most un-directed races in the game classwise, although they have slight bonuses in their Heavy Armor, Blade, and Blunt skills, they really have no restrictions on being a stealthy or magical character, and can be considered the "Jack of All Trades"
Every nameless guard in Cyrodiil is an Imperial, clad in appropriate uniforms (either Imperial Legion or a variant of Steel Armor or Chainmail Armor). Among the vampires, the Healers (mislabeled as "Sorcerers") and Monks are Imperials. Marauder archers and warlords can be Imperials as well.