If you're looking for the best, I'd say the Canon 5d mark3 with the Canon 17mm tilt/shift lens. But that might be overkill for your needs and budget.
The Canon T3i or Nikon D5100 would both be good options. A tripod would be more important than a fast aperture lens. Keeping the camera perfectly level is very important when using a wide angle lens. Plus with a tripod you can shoot longer exposures in low light and still get sharp photos. Shooting on a tripod at f/8 will be better than shooting handheld at f/2.8 anyway.
If you get too wide you'll get distortion at the edges of the frame. But if you want really wide, look for something in the 10-12mm range. Just make sure it's NOT a fisheye lens.

Thank you. That is very useful advice. I am leaning towards the Nikon D5100 myself (the Canon T3i isn’t available in India and the Canon 5D Mark III is way too expensive for me), but is the Sony SLT-A57K a worthy enough contender?

As for the tripod, is the GorillaPod SLR-Zoom worth a look? http://joby.com/gorillapod/slrzoom

That Sony DSLR would be fine. But I would get a full size tripod, not a Gorilla pod.