There are two camps:
A) A loss is a loss - 0 points, no soup for you.
B) Symmetry is important. Every game should be worth x points.
I'm firmly in camp B. I don't mind the fact that, in the IIHF system (3-0 split for a game that ends in regulation, 2-1 split for a game that ends in OT/SO) that you're awarded a tiny morsel for making it 60 minutes without outright losing. I'd have no objections to making it a 3-0 split in regulation/OT, and a 2-1 split for the SO; either way is fine by me. In fact, I'd have a slight preference to this way. It essentially means that before a shootout, the teams get 1 point apiece for the "tie", and then play a 1 point shootout - devaluing the shootout, which is ALWAYS good.
I just really like the fact that, in the IIHF point system, every game has 3 points up for grabs. It's necessary to make fine distinctions among regulation wins, OT wins, and SO wins in the IIHF, because they have relatively short tournaments. It may be less necessary in the NHL regular season.
My ideal scoring system, however, would be a 2-0 split for regulation/OT, and a 1-1 split for a tie game. That'll never happen, because shootouts are allegedly great.