I am a level 55, no prestige because I don't feel like doing this all over again just to get a pretty picture next to my name.

I play all sorts of gametypes, mostly Hardcore S&D/DM, but also Sabotage(for my last challenge), normal team DM, headquarters, and free for all, which I dominate at all times with War.
These are my current setups, the four horsemen and EPIC.
War: My only purely non-hardcore setup. It rapes face.
-Used for Team Deathmatch, Free-For-All, Sabotage, Search and Destroy, and some other non hardcore gametypes.
Red Tiger G36C w/ silencer
USP Silenced
-Bandolier/Frag x3
-Stopping Power
-Steady Aim/Martyrdom
First perks for more open maps, second perks for closed in ones. It is an amazing gun, and the silencer reduces the recoil to almost nothing for amazing accuracy. With stopping power it easily kills in about 3 bullets, while ammo is no problem when bandolier is equipped. It is a quick killing machine good on any map, and my personal favorite.
Pestilence: My sniper build, designed to infiltrate and decimate.
-Used for hardcore and non-hardcore gametypes of all kinds, depending on if the map is good for sniping or not.
Red Tiger MP5 w/ silencer
M21 no attachments
-Claymore x2
-Overkill
-Iron Lungs
OR
Red Tiger Dragonuv
USP Silenced
-Claymore x2
-Stopping Power
-Iron Lungs
Finally got my RT MP5!

Best looking gun out there, and great for sneaking into enemy locations to snipe from. For hardcore modes I use the first setup, and for non-hardcore I use the second one. The claymores set me up for great camping spots while I pull off headshots quickly and easily, and take out anyone nearby with the MP5 or USP.
Famine: My headshots build, currently used for SMG's.
-Used only on hardcore gametypes, as it is much easier to pull off headshots for kills than in other games.
Blue Tiger Skorpion/Mini Uzi/AK74u w/ ACOG or Silencer
USP Silenced
-Bandolier
-UAV Jammer
-Steady Aim
A pure hardcore setup, this is where I get my SMG headshots. Currently done with the MP5 and P90, I only got about 50 headshots to go on each of the other 3! The setup is designed so it has loads of ammo to keep me going, while still being quick and accurate for easy headshots with steady aim. UAV jammer of course is great so they don't see me coming for even easier kills. I use the ACOG scope because it seems to simply attact headshots like a magnet, I have no idea why. Sometimes I'll use the silencer though, simply for the fun of it.
Death: The LMG headshot build, designed to survive while inflicting massive damage.
-Used mainly on Hardcore Team DM for easier headshots, but it can be used in other gametypes as well.
Digital SAW/RPD/M60 w/ Red Dot
USP Silenced
-Bomb Squad
-Sleight of Hand/Juggernaut/Stopping Power
-Deep Impact
For hardcore modes I'll use sleight of hand just to cut down that awfully long reload time, but normally I'll just throw on juggernaut to make people mad. xD They are all relatively easy to get headshots with while using the red dot sight, and bomb squad is just there to help keep me alive in buildings. It works for me!
Epic: The killing machine setup. G3 F T W.
-Used exclusively for Hardcore S&D and Team Deathmatch to optimize it's killing potential.
Red Tiger G3 w/ Silencer
USP Silenced
-Whatever I feel like using.
-UAV Jammer
-Extreme Conditioning
The ultimate stealth killer in Hardcore. It's quick, accurate, and kills just about anybody in one hit. For the first perk I'll use either claymores, bomb squad, or just bandolier depending on what map it is to get the full effectiveness out of it. Extreme conditioning helps loads for getting the jump on enemies and getting away from trouble quickly. UAV Jammer is self explanatory here, I don't wanna get shot at!