IMO the SP is far more important, since it's the part of the game where you learn all the mechanics of said game. Borderlands multiplayer was just genius to me, it wasn't a separate mode, it was just the same world and storyline but with your friends hopping in and out. The game already overflows fun, and playing with friends multiplies it.
GTA Online also was great and addictive, the idea of you being you on Los Santos and earning money by yourself with hard work and even competing against other players was a great addition. I got to level 42 but stopped playing when everyone started hacking and cheating, and I believe that as good as a MP is hackers and cheaters are unacceptable.







