The 14-45 as mentioned previously will definitely be wide enough for the time being, but for the future I would look into getting either a Tokina 11-16 or the Panasonic 7-14 for wide angle. Those two lenses are definitely the best options. Personally I would get the Tokina, but the Panasonic does have an advantage in regards to the fact that it is a native micro 4/3 lens, so no adapter is required. Both are great options.
Also, definitely look into getting a good tripod, it is an often overlooked piece of equipment in the age of glide cams, but a tripod is crucial, as it allows you to get much, much better static shots, which in my opinion are more cinematic and look very professional if done right. I personally would recommend the 701, and also look into getting a Manfrotto quick release plate as well, it will be awesome if you get a glide cam, and helps out A LOT!
For some lenses, look into some older Canon FD lenses, or older Nikon/Nikkor lenses. You can find absolutely fantastic lenses for insanely cheap, just because they are old. The Canon 50mm f1.4 S.S.C is a fantastic lens, as is the Nikon equivalent. Also, older 28mm f2.8's are great. Another awesome lens is the Nikkor 135mm f2.8, which would definitely work as a mid-range telephoto lens considering the GH2's crop factor. You do need adapters for these lenses, but thats not really an issue. I use Fotodix adapters, and they are solid.
For accessories, extra batteries are CRUCIAL. The GH2 has average battery life at best, and on cold days it is really quite short, so undoubtedly stock up on batteries. The good Lumix batteries however run around 50$, so keep that in mind. Also, get good ND filters for your lenses. I like the LCW Fader ND filters.
Finally, a good mic, like the ever popular Rode Videomic Pro is a very good thing to have. A lot of people overlook sound in their edits, but personally I love the sound of skiing, and think it adds a lot to an edit.
Tokina 11-16 (around 600-650) OR Panasonic 7-14 (900) for WIDE ANGLE
Manfrotto 701 head (125 on B&H) for TRIPOD
Older FD/Nikkor Lenses will usually run you around $50 to $150 (max) depending on the lens, and they really are great.
At least two extra batteries ($100) and good ND filters (about 110 each)
Rode Videomic Pro (225-240 depending on where you get it).
*Optional* Glidecam HD2000 ($500).
Sorry that was long, but thats just a list for the future, and is pretty much everything you would need, other than a telephoto, and for that I recommend a Nikon 70-200 undoubtedly.