Agree with sexytw, but does sometimes depend on what you are shooting to an extent, if you are just taking straight photos you are fairly safe, but if you are taking action shots a faster shutter speed and faster memory write is very useful (Used to have a 300D and that was slooow) But also if you are venturing in to SLRs be aware that its not just go out and buy one camera and one lens, be prepared to get you camera with a stock 18-55mm, then buying a zoom on top of that, then maybe a prime or a wide angle, fast memory cards, then you need a bag, then you want a tripod, maybe some filters, off camera flash.. .and by that point you have spent quite a lot of money
... Then you want to get a new body
But there are some good deals out there, and if you are looking at SLRs Nikon or Canon seem to be the choice in most cases, dont go Sony, not because its rubbish, but there seem to be more 3rd party lenses available i.e. Tamron etc, and you can get good lenses at a better price.