I'll depart a bit from Johns take on this and say - if you have the intention of using the camera in a very full manual way, the D90/50D would be a better alternative to the XS. They have more on the fly switches, dual control dials, faster AF, etc all stuff that makes full manual modes (A/S/M) easier and more functional to use. However, if its dummy modes you plan on using anyway (auto+anything else), the added investment is pointless, even counterproductive. In which case, definitely get a 17-50 f/2.8 or something for your XS, instead of wasting money on a nicer camera out of vanity.