Power handling has no relevence to output, and neither on sound quality either. If volume is all you want, look for efficient speakers 100db+ 1W @ 1M, and 8ohm impedence. You'll always want a decent amplifier, otherwise if the amplifier just clips say goodbye to your tweeters....and it'll sound horrible.
A 15W Hi-Fi amplifier with efficient speakers will very likely sound better, and play louder than a 1000W PMPO PC system.