You won't go far wrong with speakers from Altec Lansing (top US hi-fi speaker manufacturer), Creative, Logitech and similar quality manufacturers - the more you pay the better should be the sound quality.
Scan of Bolton (click here) sells Altec Lansing as well, amongst others, and its TodayOnly page often has special prices for speaker systems.
Because, I would guess, the company has many, many years of designing and producing high quality speakers for hi-fi enthusiasts.
Speaker systems are not just boxes with speaker units in them....:-)
Creative, Logitech etc supply good speakers and value for money, but they don't have the same background in the technology and, I would suspect, rebadge other manufacturers' products under their own name.
By coincidence I am still grinning with pleasure from my new Altech 221. It was more up-market than I had intended, but the quality of sound is superb.
Some of the smile has gone from my face because I am having appalling problems installing a new Creative SB 4.1 which will not live with my HyperOS Win98SE system. I thought better speakers deserved an alternative to an onboard sound system.
I'm going for a Hercules GameSurround sound card, recommended by a friend very much into music...but oddly enough he recommends a Creative Inspire 4.1 set. Problem is, I just don't have the space for a 4.1 set! Maybe I will go for the Altec after all. After all, they were recommended by the best PC magazine ever ;-)
Buy the Altec Lansings and your ears will provide all the evidence you require, but make sure you have a good soundcard to get the best out of them.
Remember, if you put rubbish in, then even the best speakers in the world can only put rubbish out.....
Creative is not, as you suggest, primarily a soundcard company although it produces good ones, but specialist manufacturers are the way to go to get the very best; that's a rule that applies to products of any nature.