I agree with Mike too about salesmen, however up in Carlisle we are lucky to have Peter Tyson's who have a dedicted room for tests.
Hey, Peter Tyson is a good firm! I have ordered stuff from them.
Rob is right, getting the right compromise between music playback and surround is tricky. Like him, I too have better quality speakers instead of the usual tiny ones as the latter don't deliver on music playback, even when supplemented by a subwoofer. My fronts cost £70 on eBay (£200 new, a few years back, RRP £400) and a center to match cost me £150, I think. The biggest investment was the sub, which was £350. Rears are smallish bookcase sized Tannoys that at one time I had at the front. The AV amp cost £350, and has 4 more channels than I use. Considering this is quite a cheap system(!) you can see that is soon mounts up. I didn't go overboard with the speaker cables. I tried that once and it made no difference whatsoever to sound quality.
So I have a mixed system with Monitor Audio front, Tannoy rear, Tannoy sub, but it sounds great to my ears. The amp is Onkyo, but if I bought again I might go for Yamaha. I had a Yamaha but it had too few hdmi inputs. I would also go for one with firmware upgrades, as the amp seems to be the biggest cause of hdcp problems.
As gomezz said, I could improve the front speakers, but that would involve paying at least £400 for a pair, even discounted (plus more for centre) and I can't really justify that.
So, I would pick up a cheap surround system with a separate subwoofer and gradually improve the speakers. Some of the cheap ones have the amp and sub integrated, not good. Even a cheap system will sound loads better than two front speakers, for watching films. You can tuck the cables under the carpet, or tack them to the skirting board.