Depends on what you want to use it for. Farming, tfs, teaming, solo? A high recharge farming build is quite different from an exemplar friendly tf runner.
How much are you willing/able to spend? Are purples or PvP IOs a consideration or out of your price range?
If you don't have Mid's, I suggest picking it up and experimenting with a build. If we have somewhere to start we can help more, otherwise we're shooting in the dark. 
Also, not to sound snarky, but search is your friend. This comes up a LOT.
@ Sfort
Post may sarcasm
Leet speak, and generally difficult to read posts will be not be read.
OAS! AAS! LLS!
alohaz all!! i need advice for a arch/mm build. i have a 50 all rdy just need some advice so i may respec n make him better. tyvm alohaz!