It depends really, on the situation, at a distance, AK-47, short distancee M4A1 Silenced, but my overall favourite weapon in CS would have to be the SG552 along with the Desert Eagle (Which is now over $2000 with the new dynamic pricing I might bloody add!!!)
I love picking people off with a couple of shots from an AK. Nothing funnier than popping out and knocking off a few enemies without them even seeing me...
Although I do have a fond memory of taking out the entire other team with a Desert Eagle..., very fun!
For the price, the TMP isn't bad at all. Most people dont use it but it has a high rate of fire, very low recoil, decent acuracy, and of course, it's silenced.
I had a buddy in undergrad who absolutely loved and for some reason could completely own us with that stupid basic SMG. Really made me mad at times, and of course he'd giggle like a little school girl while doing it, too!
He would do it even worse when we would play just straight multiplayer of HL1 with the double shotgun. He had some amazing reflexes. He would like jump and right-click and the same time like someone was hitting him with a reflex hammer...