Ah, I see. I'm quite new to all this. Aparently they each have a mid-woofer with an input resistance of 8 Ohms, and a 4 Ohm tweeter.
Creative GigaWorks S750 Speaker System Review: Beyond Ultra Sound (page 2) - X-bit labs
Can you suggest a good sub to go with that for about £100 (is this even possible?)? I'm mainly interested in music quality (mixture of everything; electro, punk rock, mashups, rock'n'roll, classical, possibly a bit of jazz) but if it could work well for films as well, that would be great.