Congratulations on your new toy!! You'll love it.
Re: fisheye, when I first started photography I thought a fisheye would be a good way to go, but I've since realised that unless fisheye is a REAL passion, it's only ever going to be an infrequent use specialty lens. Cool effect, yes, but not overly useful except in special circumstances. I would suggest adding other lenses to your collection first. Probably something wider than 28mm should be your first step, then maybe a 50/1.8, and then you'll know what you really want (if you want/need to change at all).
I still don't have a fisheye lens (and my kit is worth an arm and a leg). But for a 30D, the only cheap-ish true fisheye I've seen is the 8mm Peleng (full-frame fisheyes aren't very wide on 30D's). Very much a specialty lens too.
Hope that helps 