20D Body for sure, it is far more robust than the XT.
Other than that, don't discount the comments about travelling light and low key.
I would keep a 300mm f4L IS in another nondescript bag with a 1.4x TC if you need it for the occasional long shots. The 1.4x produces much higher quality shots than the 2x, and the price of the 300mm with IS can't be beat for that focal length. Usually if you really want to zoom you will have it at max focal length anyhow.
The 50mm f1.4 is a brilliant and affordable street photography lens, but in your case you might want to go with a zoom to minimize the number of lenses on your person.
Don't worry about the 150-300mm range really, either you need variations under it or much more. The 17-85 is a nice lens, and lightweight, but the constant f4 and L glass on the 24-105 will be much nicer.
If you like wide, get the 10-22. Between those three, with only the body and the smaller 2 lenses in your main bag, you can cover a great deal of range and not haul a ton of expensive looking or bulky equipment. With IS on the 2 longer lenses, you can probably get by without a tripod as well, but bring a beanbag just to be safe :G
Have fun!!!! Sounds like a wonderful trip!