Winchester and HK SL8 are imo the best balanced and my favorites. Now, what I end up using most of the time? AK or Shotguns because you pretty much have to in order be competitive.
I favor the colt as a secondary and the rifle as a primary. I used to shrek with the rifle, but lately I have been failing on an epic scale. So don't watch me :X
p90 master race. It's very accurate, has a large ammo clip but isn't too slow to be ineffective. It's not as good as the scrubble barrel but what good is a db on metropolis? ( no one say anything about the rooms, please. ) As for secondary I prefer the deagle since it has an awesome select animation and I find it better than the colt. ( iirc it does more damage and has a higher firerate, and I'm not accurate enough to secure headshots. )
Starting to feel the love for P90. Like Han Solo said, huge clip, accurate, and high rate of fire. It's like some weird hybrid gun, and I love it. Starting to pick it up a lot more recently. Also, the Colt sucks. Deagle all the way.
It's the double barrel whenever I can get my hands on it. Most of the time I stick to the Mossberg shotgun.
Silenced Pistol. I feel like a wet works agent when I use that gun, I can see it in everyone's head as the gears turn "Is he shooting me?" but they are usually dead the second that thought finishes. Colt is OK too... I guess...
I'm a big of fan of a bunch of guns. Sniper - AWP Rifle - AK/47 Traitor - Harpoon, C4 or Newton Launcher Detective - Jackhammer