Check out this thread:
Canon DSLR users - lens help
I asked some similar questions there and got some good responses. Also, the major canon forum seems to be
http://www.photography-on-the.net/forum/
A good portrait (50mm 1.8), a good walk-around (many in this category), and a good tele-zoom (70-200 or 70-300) would pretty much cover the gamet. Then you can concentrate on some more specialized lenses like wide angle (10-22mm or 17-40mm), fast lenses (24-70mm), and primary lenses (many in this category too)