Borderlands is sick, Dead Island is not as good but still very fun (I really like the whole RPG/FPS steez). If you buy all those games at once i doubt you will become wrapped up in Dark Souls though, it's too frustrating compared to the other games.
Borderlands is such an awesome game, can't wait until Borderlands 2 comes out. Dead Island might be more of a hire game I think. Way too many games to play.