I can't wait for Pikmin 2. I *loved* the original Pikmin, but it was too short. If this game is long enough to be worth it, I'd gladly put down $50.
Multiplayer should be very interesting. Personally, I'm hoping for something similar to the multiplayer of Zelda on GBA, from what I've heard of it. It would work great with Pikmin, it would fit the style perfectly. I just hope they go easy on the puzzles - the last stage of Pikmin seemed a bit too much like Zelda for me - too obviously designed as a puzzle - it didn't have that natural wildlife feel that the rest of the game was so brilliant at.