If you buy a telephoto lens past around 200mm I have to say get some sort of image stabilizer or the lens will become quite useless.
Sorry Jase, have to disagree with you here. Photographers have been happily using non IS-equipped telephoto lenses beyond 200mm without image stabilizer for many years. It really is only a recent
(and very welcome) addition to modern telephoto lenses.
For daylight usage, you should have enough light around to shoot 1/250th or faster which, on something like the 70-200 f/2.8 is enough to obtain sharp images without resorting to IS/VR etc. Image stabilization is handy when your shutter speed 'falls' below that of the reciprocal of your focal length (for example, 200mm = 1/200th).
So, in darker conditions, with my 70-200, I should be able to regain those few stops of shutter speed through the use of IS/VR. I hope that made sense
You also have to factor in the crop factor also when considering the above rule-of-thumb.
whitey89: I'd sooner look at something like the 60D which offers a bit more of an upgrade over the 500D.