Too many unknown variables to give you a good answer - your room (size, shape and acoustics), your speakers (range, sensitivity, impedance curve, plus a sub) your personal listening perferences (how much SPL do you want). Keep in mind that receiver power specs these days are usually highly optimistic and based on one or two channels at full power. A separate power amp will usually be conservatively rated and capable of real world power ouput many times a receiver. In general, the bigger and more absorbent the room the more power is needed. For speakers, the lower the sensitivity and impedance ratings the more power/current is needed. And if you like to hear your system twice as loud as average you will need 100 times the power to achieve that (an unlikely scenario lest you go deaf). More power will sound better at higher volume, all things equal, and will help protect your speakers from damage from amps clipping (overdriven). Also keep in mind that much of the higher price paid for flagship receivers with high powered amps is in the amp section. By investing long-term in a good separate amp you can ignore receiver power ratings and just select one based purely on the features you need, as long as you have full preouts. My personal favorite is the Sherwood Newcastle A-965 that sells for around $1k street, has a 5 year warranty, and will drive low impedance speakers without a problem, something most receivers have trouble doing. But in the end only you can decide whether you like what you hear with a separate power amp and whether it is worth your investment.