I am, horror of horrors, actually building a small home theater system in a back bedroom, and am going to use the smaller Dynaudio Audience 42s for the system. In listening to a couple of AV receivers with them, the one that stood out as the best sonically with it to my ears was the current $1300 Rotel unit, and not by a small margin, either, compared to the $500 Marantz I was listening to (closer call with an Arcam). I would therefor recommend a Rotel amp (assuming you just don't go whole hog and replace the Yamaha); whether you can do it depends of course on whether your Yamaha has a pre-out function, or at least a tape loop. Not knowing how the Yamaha works, if it does have a way to bypass its active preamp circuitry (usually through its tape loop), get an integrated with a better pre section than the Yamaha's; if not, then it makes no sense to go through two active preamp circuits vs. one. I think you'll find that a lot of the Yamaha's sound comes from its preamp section; using it with a warm-sounding amp may not necessarily cure the problem.
