Replacing XTi Kit lens

Forgive any ignorance here, just an ameture:

I've had my Canon XTi for about 2 years now and want to upgrade/expand from the 18-55mm kit lens. I do mostly nature/wildlife photos in the CO Rockies and Appalachian Trail. I also do a significant amount of architecture/monument shooting in DC. Right now I'm looking at 2 lenses to get the broadest range I can at an affordable price. My current top choices are:

Tamron SP AF17-35mm F/2.8-4 Di LD Aspherical (IF)

and

Canon EF 28-135mm f3.5-5.6 IS USM

Would these be good options or would something else work better. Thanks for the help!!

I would have thought that a telephoto zoom would be most useful for nature/wildlife so I would probably look at something like a 75-300mm.

This would complement your existing 18-55mm.

Hope that helps!

John