I also recommend considering the Think Tank Streetwalker. It is relatively compact and can easily fit my Canon 7D with an f/4 70-200 with lens hood attached (NOT reversed), a 135 f/2, and a 24-70 f/2.8. I am sure I can find space for my 50 mm prime too. Lots of side pockets for water bottles and a compact point and shoot, inside pockets for CF cards, cable releases, and a large Giottos Rocket Blower. Don't forget that you can also attach a tripod to it. I used it hiking in the Southwest National Parks and was very happy with it. The straps allow one to carry additional CF cards, lip balm, or a sunscreen stick. They're a little hard to find but as with any bag purchase, grab your gear to see how things fit. Call around to see if any local camera shops carry them. Adorama but not B&H sell them online.