you have just brought up the sacred subject of "a/v receiver vs. separate pre-amp/amplifier" debate. It really will come down to "total budget" in the end.
Modern a/v receivers by H/K, Denon, Onkyo, and Marantz (typical consumer level a/v equipment) is very good and more than adequate for today's in-house home theater setups.
Pre-amps and power amplifiers are harder to find at consumer level pricing and are usually audio speciality items sold through audio dealers. When you need a lot of solid power to the speakers, separate power amps have a definate advantage over most mid-level receivers. But even that advantage starts to fade when you consider top of the line a/v receivers against pre-amp/amp setups.
One way to by-pass the debate is to buy a solid a/v receiver which also has separate channel pre-outs. You start out using the receiver, and if you find you really need more power, us the pre-outs to send each channel to a free standing power amplifier......best of both worlds.
What are your "needs", budget, room conditions, music vs. movie sound tracks, preferences in speakers (towers vs. bookshelf), overall room size ???