it is also EXTREMELY helpful for doing self-family pictures (where you want everyone in the shot). You flip the viewfinder all the way out, then can look in the viewfinder while positioning everyone - including yourself... Then go set the timer and get back in.
easier than positioning everyone except yourself and hoping you get into the picture decently
We have done this a lot. I just sold a canon point & shoot (SX10IS) that had this screen - liked it a lot.
I just ordered a 60d with 18-135 IS lens. I think it came today and I'll be having fun figuring it out in the following (weeks/months?).
Have heard a lot of good stuff about that lens (as well as the 18-55 kit lens that I believe the rebel's come with.) Just be sure your lens has image stabilization.