Depends how you play... If you're more "recon-style", you'll probably shoot less (so less space is needed for ammo) and will want to keep your setup light. An LBV could be a nice choice.
If you're more "assault", sometimes doing covering fire, going a bit less stealthy, etc... In short, more "grunt style" a PC can be better.
I've said CAN and COULD, since there isn't any rules on this... it's down to personal preference
. An "assault" guy could still be able to play with only a blast belt, it may just not be the optimal setup. But just go with what you're confortable!