I use a LowePro Trekker
I can carry my 10 and an A2 as well as my 3 most used lenses which covers me for all occasions. In the pockets I have room for memory, readers, film, flash, batteries, etc. and there is an external strap mount on the bottom outside of the bag for my tripod.
I think I paid about $60 - 80 for it new.
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"I'll keep my money, guns and freedom. You can keep the "Change."