As the T3i/T2i/60D all have the same sensor, and will provide the same visual result, you need to decide if the additional features are worth the additional cost. In the case of landscape photography, I think the T3i would be the best choice as the variable angle screen would be quite advantageous for tripod work or anything involving inconvenient angles. The price jump to the 60D gives you a bit more FPS (not important for landscape work) and a significantly better viewfinder. Ergonomics also come into play, but that is a personal thing based on your hand size/shape. You need to decide what criteria are most important to you and make your decision based on that.
If you are looking for a decent lanscape lens, the Tamron 17-50mm f/2.8 (the original, non-image stabilized version) is a great option to start with. Otherwise the wide angle options by Tokina (11-16mm, 12-24mm) are generally superior to Canon's APS-C offerings.
Another option you could consider is to ignore APS-C sized sensors and get a lightly used Canon 5D (the original) for about a grand. Despite its technical obsolescence, the image output of original 5D still crushes any crop sensor out there for landscape work. The lack of sensor cleaning and live view are the most significant drawbacks. But if you really want to get into landscape photography, the 5D classic is the most economical route to get the best output.
Here are a couple example shots from my 5D (all with the 17-40L)
Lower Lewis Falls by
posthumus_cake (www.pinnaclephotography.net), on Flickr
Crashing Cape Kiwanda [explore 9/22/10] by
posthumus_cake (www.pinnaclephotography.net), on Flickr
The Mountain by
posthumus_cake (www.pinnaclephotography.net), on Flickr
-Matt Peterson
http://www.pinnaclephotography.net/