If I had to choose just a couple lenses, I would choose:
- A fisheye that will work well on your t2i. Probably just whatever the canon one is for crop sensors. Some people don't like fisheyes, I think the distortion can be real good if done well.
- a super wide, maybe the tokina 11-16. that's not much zoom range, but if you're going wide, you are doing so for a reason.
- a medium zoom, something in the 24-70 range. There's LOTS of lenses in this category, so shop around. Some people prefer the 18-whatevers over the 24, I find I rarely feel the need to shoot between 24mm and 15mm.
- something that's 70-200 ish. Again, lots of options. There's a 70-200 f4 in the canon L series that it seems like people like, but I don't know much about the canon lineup.
This is all personal preference, it all depends on the shot you want and what sort of skiing you like shooting. I also don't know what your price range is. Hope that helps though!