If you're using a high-powered sub as well, I'd go for the 5125 (extremely clean-sounding amplifier - great choice!). If you're using just the speakers listed, I'd recommend the 250 watt amp, especially in a room that size.
Out of curiosity, how far are you sitting from the speakers? How loudly do you want the system to play?
Out of curiosity, how far are you sitting from the speakers? How loudly do you want the system to play?