I'm also a canon fan, however, I wouldn't really jump on that deal. Spend some time checking out the XTi. The 30D has been out a while, and it wasn't much of an upgrade from the 20D in the first place. The rebel series has improved dramatically since the 300D, the only thing I miss on mine is the rear control dial, but that certainly isn't worth the $500.
As to the lens, I've never used the 28-135, but I've used the 28-105 f3.5-4.5, and the 17-85 EFS, and the 17-85 is really a great walk around lens. I use the 17-28 range far more than I used the 85-105 range. The IS is supposedly better on the 17-85 also, and I'd certainly vouch for it being useful.
If I were you, I'd splurge on the XTi and the 17-55mm f2.8 IS lens, that's an amazing piece of glass. Only two hundred more than you're looking at with the 30D+28-135, and a much more versatile lens when it comes to low light situations. The lens will be worth far more than a 30D in a year.
As to the Canon vs. Nikon debate, it's not one I pay attention to anymore. Back when I picked a system, canon was usually ahead on the R&D front, slightly less expensive, and they had more options when it came to current lenses. Since then, I haven't looked back, as Nikon would have to be extremely compelling to switch systems.
Matthew