To Apple_iBoy and andiwm2003. I played with the A100 in the store the same time I played with the Nikon D40. I really like both. My problem with the A100 is that the majority of people said don't get it. They said that at the moment there are no upgrade options, and may never be. I don't want to invest in the body, and multiple lenses and then have Sony just stop making SLRs. I do really like that it has IS built in, and I love the autofocus when you put your eye up to it! I've been very happy with my H5 and have had a few Sony camera's before and they all still work great. It's a tough decision. I'll have to look into the A100 a little more. Another bonus is that Sony will let me trade in my H5!
sony will release two upgrade bodies this year and the a100 will eventually get a better chip. so the upgrade path is there for the next years. after that who knows. but that is true for all brands. for e.g. you can't use pre ef canon lenses on new bodies.
IS built in is great. i love that. the autofocus sensor at the viewfinder sounds cool but honestly you press the release halfway down when you look through the viewfinder anyway. and if you carry the camera and something gets close to the viewfinder if focusses and wastes battery time.
the trade in issue is not too great. you can get the sony discounted somewhere else cheaper than with the trade in.
contrary to some other posts i feel the body has a good quality.
a number of people like it. as i said, all brands are good right now. canon has the least noise. if you shoot sports and in low light consider that.