The best class for me is:
M16 - Red Dot
Stopping Power
Deep Impact
* Frag x 3 (lvl 41) - just because they are fun to bomb people with... hehe


The coolest thing is that you get all these from the start :o)
* Expept for the red dot but hey, 3 or 4 games will do the trick ;o)

Happy Gaming!
Power_Dude