Any suggestions?

Recently I've been running out of thing to play. I get bored so easily, yet not sure what to play. I like first-person shooters. Borderlands series being my favourite. Anyone got any suggestions for long games?

Doom 2: Hell on Earth via the gZDOOM source port. I strongly recommend getting Brutal Doom as it pretty much rebalances EVERYTHING.

Far Cry 3 can be made to be quite long if you don't just do the main objectives, there's a lot to do in the world.

Well it's not a shooter,but have you tried Dead or Alive 5.Pretty good,in my opinion.