How happy are you with what you have for the kinds of pictures you are shooting, or want to shoot? I like letting necessity drive my camera purchases, so the first things I usually address are my frustration points with my current gear: Are you getting frustrated not having a fast enough lens or fast enough AF indoors? Or perhaps when you're outdoors trying to photograph a building and the darned kit lens 18mm isn't nearly wide enough? Are you bothered at all by the build quality of the lenses you have?
The 17-55mm is a nice upgrade from the 18-55mm kit lens, because of the f/2.8. It will let you keep that lens on in many situations where you'd want to swap out the kit lens for the nifty. The 17-55 build quality isn't L grade, but it's better than what you're used to so far, especially with regard to the AF mechanism (ring USM with full-time manual is where it's at). If you go this route, you won't use your 50/1.8 much, unless you just love super shallow shots. The prime 50mm probably has a little sharpness edge over the 17-55 @ 50mm f2.8, but the 17-55 has image stabilization, which is very, very useful with still subjects for keeping your ISO down.
The 10-22mm is built like the 17-55, and can share filters (both 77mm). They complement each other nicely. The 10-22 is wide, wide enough that you won't want it wider. 10mm is often too wide. This is a great lens, but I wouldn't personally prioritize it over getting a better and faster standard zoom, unless you're totally happy with your kit lens for that role.