Re: the kit lens, I had already ordered the 18-200 when I purchased the XSi, and I purchased it with the kit lens (focally redundant because of the 18-200) anyway.
Honestly, I almost never put it on in serious "oh my God I have to get this shot" situations. But on the other hand, when I want something light and easy, it's great. It's the only lens that I don't feel like I need to protect like a child, so if I'm going to take the camera out drinking with me (it prefers Dos Equis) or just want to throw on something quick to take some test shots (or let a friend take some shots...) I love having something that I didn't pay an arm and a leg for.
And honestly, the IQ is great.
Oh, and, yeah, you're going to want something wider than 35. You'll want an UWA sooner or later... but that's a question for another thread 