Yamaha RX-V757 with Klipsch F2 speakers

I don't know too much about the F2 but I use the rx-v757 with Klipsch ChorusII and Quartets before that. The yahama is a great HT receiver and very easy to setup but I use it for 2 channel listening as well. For fun, I've used my laptop as a source to it via a toslink cable to listen to mp3's. I have read that the yamaha's are bright too but I don't notice it in my setup. But see if you can try it before you buy - it's the best way to find out if it works for you.

Both of those components you are refering to are likely on the bright and analytical side (Refering to the Yamaha from past experience). I would NOT mate them together personally, as they don't compliment each other well(speakers/receiver). I'd go with a warmer more forgiving sounding receiver in the Denon if you already own those Klipsch speakers. The old Synergy series speakers weren't as bright and hollow as the newer series, FYI. I know, I've owned and compared em both.
Also, the new Denon's have an INDISPENSIBLE Audyssey MultEQ system that's superb, and much better/more effective than the Yamie's.

Maybe you could try it out for a few days?