I like to mix it and don't stick with just the one weapon/class but some of the kits I run with are.
Assault
For super try hard mode and close quarters
AEK-971 HB+KOBRA
M1911 Tact
Med pack
Difib
For larger maps
AK-74m HB+KOBRA (maybe SCAR-L or L85 )
G18 supp
Med pack
Difib
Engineer
I mainly use the ACW-R, it has the highest minimum damage over range out of all the carbines, especially with the HB. It also has low recoil and hardly any bullet spread.
ACW-R HB+KOBRA
M1911 Tact
SMAW/RPG
Repair Tool
AKS-74u HB+KOBRA
M1911 Tact
SMAW/RPG
EOD BOT
Support
I really dislike the Support class, too many people with no skill use it to just hold down the trigger with an LMG and spray and pray all over the place. Either that or they just camp in one spot bipoding all day erry day. Not saying all people who play support are like that but there are a lot of people who are, from my experience anyway.
My exact thoughts when I see people doing ^^^^
http://www.youtube.com/watch?v=Jluk8b9MEnM
If I do run support, the only kit I really like is
MG36 HB+Extended Mags+KOBRA
G18 supp
C4
Recon
The riffle and sights I use depends on the map and situation, I always use the strait pull bolt though. I never use the silencer because the reduction in damage and the increase of bullet drop is ridiculous.
For close quarter maps the M40 is the best in my opinion because it has the fastest rate of fire, meaning there is less time between shots. Which if you are on a small map and miss the headshot and you need to go for the two shot kill you have a higher chance of killing someone before they kill you.
For long range it has to be the M98B, it has the highest muzzle velocity meaning less bullet drop and it also has the highest maximum damage at 95.
Scope also depends on the map and situation, long range 12x, medium 8x and for close range either the ACOG 4x, PSKA 3.4x or even KOBRA or HOLO. All of which give off no scope glint.
For gadgets I always run with the spawn beacon and depending on the map and game type either the MAV or SOFLAM.