Well, im assuming your playing the stock game so here..some perks may change depending on TDM/SD but these are the best all around kits hands down. Hardcore and Softcore.
M4+red dot w/ bando,stoppingpower+steadyaim
AK47 w/ bando,stoppingpower+deep impact
AK74u w/ bando+stoppingpower+steadyaim
MP5+red dot w/ bando, stoppingpower+steady aim
RPD+grip w/ bandolier,stoppingpower+deep impact
Deagle is the best pistol, dont waste time with anything else.
Those setups are by far the best all around kits in the game hands down. generally you;ll notice that opfor guns generally have much better ironsights, where as you get much better results from a red dot on an american gun.
There are only 5 or so good perks, more ammo, more hitting power, more power threw walls, and better hip accuracy. Other than that the other ones are not worth it. Dead silence is ok if you want to be sneaky but meh, ive never really needed it
Some other goodies;
M16+red dot, bandolier,stopping power+deep impact
G36+red dot, bandolier, stopping power+steady aim
MP5+silencer, bandolier,doubletap+steadyaim---->one of the best guns for CQB in hardcore mode, high rof+quiet+lots of ammo+looks sexsi
M40A3, Claymores,Sleight of Hand, iron lungs
However,if you want to be supremely gay/cheap, use:
P90+silencer, claymore+uavjammer+deadsilence
If you want to get good fast you should play on servers running promod though, as the competition there is alot better and you;ll find that after playing on those servers you can go back to any server running stock/hardcore and outgun anyone there.