Well as a stunty player I would say go Dwarf (who doesn't love beer guzzling, ax slinging, anvil pounding, little nut jobs?). Dwarf Armies are extremly difficult to play though, as your opponent will know 85% of the time what you are going to do (sit back and pound em with war machines and ranged units). On the other hand you can surprise your opponent with things such as Rangers, Miners, Runes that allow you to move, and the anvil of doom giving you a "free" move. Nothing will put a seasoned oponent off guard like a Dwarf Army maneuvering. Basic Dwarf WS4/S3/T4 core unit: nuff said.
Orcs and Goblins have a wide diversity as far as what you might place on the board. They also have ALOT of things that can go against you just as well as against the enemy (animosity, fanatics, and troll stupidity have been good to my dwarf army at times.) Goblins have WS2/S3/T3, and Orcs WS3/S3/T4 as core. Goblins my seem like a unit that is easy to kill from those stats but when you can throw a couple units of 30-40 with 3 fanatics hidden inside to "tenderize" the enemy, numbers will be on your side. Your usual oponents will also have a hard time guessing what they might see from game to game with O&G also.
Hope this helps.