I keep the "Holy Trinity" of Carbines for every situation.
Elite Carbine- My PvP weapon, fast, accurate, and an even damage spread. Good IMO for steady damage, unlike the fluctuating Laser Carbine.
DXR-6 Carbine- I've been using this carbine more and more for both PvE & PvP, esp. when I got higher in the Carbineer/BH trees, facing tougher targets with higher energy resists.
Laser Carbine- I use this more for PvE than I do for PvP.
One more bonus for us Carbineers... our weapons look great!