sony alpha 300, nikon d60, canon eos 400d..?

the Sony a300 by far...

it's the most advanced out of the 3 cameras... it has live-view (the best in the business too), in-body stabilization, it's cheaper most likely and you get the benefit of very cheap and quality used Minolta lenses... plus you get a feature I highly value, spot-focus! love it! oh yeah and don't forget the tilting screen with rotating information...

Ditch Nikon from your list. The entry level bodies don't have an auto focus motor, that's deal breaker. So it's between Canon and Sony. If you want the best live view and anti shake in the body, not on a limited number of lenses, then Sony is the choice.