I drive my M60s with the lesser powered, younger sibling and generation older RX-V750. It is very similar in features to the 1400, which is similar to the 2400, power being different in all three (along with some higher end tweaking features). I love the way that the Yammy soudns with the M60s. The 2500 should surely be an improvement to my receiver (and if it isn't, it must at the very least, be equal). I think you'll love it.
As far as the room goes, there don't appear to be any problems, maybe with the exception of some boominess from the front right M60 (b/c of the corner) compared to the other one. However, my room has a similar set-up (with one speaker in a corner and the other placed where the room opens up). No problems, though - at least nothing that can't be tamed with bass management.
Cheers! And congrats.
