Hi OwlPig,
Just thought to share my view on this. If you are serious about photography and will be shooting for many many more years to come, I think you should not focus too much on the camera body. Most of the camera bodies in the same category (eg. Sony A200, Canon 400D, Nikon D40x, etc) are very close in features and pricing. What you can do in one, you can probably do in the other as well. Or you could find another way to achieve the same end result.
You should take a look at the lenses (original and 3rd party) and peripherals for each system, their pricing, features, performance, availability, etc and see which one suits you best. You will probably evolve on to need other lenses as you shoot on, and you will not want to be stuck in a system where you do not like the lenses, the features, etc.
The camera body is relatively cheap compared to the rest of these lenses, etc . 1 good lens can cost 2 or more times the camera body. Even the basic-moderate lenses or a good flash can cost half of what you pay for the body. So base your choice on the system (ie. the lenses, flash, etc) and not the camera body.
If you're not sure if you are going to be serious about staying on in photography, maybe you should get a 2nd hand model so you pay less for it? That way if you give up the hobby, you would not suffer as big a loss.