Just started my collection:
Body
Canon 7D
Lenses
17-40L f/4
50mm f/1.4
70-300mm IS f/4-5.6
Flash
430EXII
Tripod
Manfrotto 190XB
The 17-40L is most useful at parties and for general walking around due to its wide angle. The 50mm is just fun to use, probably my favorite lens overall. The focal length is a bit long for the kind of shooting I'm used to, but the wide aperture allows much room for creativity. The 70-300mm is a new acquisition. I've used it extensively on other Canon bodies, but not the 7D. It's going to take some time to get used to with my new equipment.
Lately I've been using the 50mm more than anything since it's so much fun, and because I'm taking portraits for the yearbook at the school where I teach. I guess that qualifies my work as semi-pro, but photography is primarily a hobby for me. I chose my camera setup because I like Canon cameras from a technical standpoint, and have been using them for many years.