I have quite a few:

1) Thru hike the AT.
2) Backpack Yosemite, North Cascade, Mt. Rainer, Glacier.
3) It would be cool to backpack the Himalayas
4) Backcountry skiing in Colorado
5) Climb Mt. Rainer or related peaks.

Unrelated to backpacking and hiking I would like to go mountain biking in Moab, UT. Go to the ice climbing festival in Ouray, Colorado, also like to just go skiing in Colorado, UT, Montana or Wyoming.
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It is one of the blessings of wilderness life that it shows us how few things we need in order to be perfectly happy.-- Horace Kephart