hkwongkit

As of now if you're on limited budget I'd recommend going for the followings combo ...
either
Canon EOS-7D, EF400/5.6
or
Nikon D7100, AF-S 300/4D ED, TC14E

You can't go wrong with either setup for a start. Both Nikon and Canon has excellent super telephotos in the 500 and 600 range.