What slr to buy

Well, that depends on how much money you want to spend on it :-) Nikon and Canon are both good, have a lot of lenses you can chose from and also a lot of cheaper lenses by manufacturers like for example Sigma. There's also lot of different models. The cheaper ones are good, but the more expensive ones have sturdier bodies, higher ISO, faster shutter speeds and better resolution. Not because they always have more megapixels but because they have better ways of saving the pictures.