Thanks for all the advices!
Finally my system is taking shape, the infinity speakers sound great with the yamaha rx-v475(80w), but i can feel the lack of power to move properly the 5.0..
So, i'm considering changing the receiver (paying some difference), and my options are:
Yamaha RX-V675 ($530 difference, 90w)
Yamaha RX-V775 ($810 difference, 95w)
Onkyo TX-NR727 ($824 difference, 110w)
opinions about this change? The onkyo is by far more powerful than both yamaha's, but i've been told that the rx-v line of yamaha has better sound quality.
Thanks in advance!