I have owned Creative in-ear headphones before and have loved the sound quality, and with the EP-630s they were no exception. I think in general in-ear headphones with the rubberised plugs seem to sound a lot better because they block out more external noise.
HOWEVER...
The biggest problem with headphones is that they almost always end up breaking at the jack where the internal wire has been bent and twisted as most people tend to wrap the headphone cable around their mp3 to store. I think it's time the manufacturers came up with a better stronger material to make the life expectancy of headphones longer, don't you?
Anyway, the EP-630s were great, while they lasted. I bought them from Play.com in May and it is now July and yes, they've broke. The sound went in the left ear and I so have been forced yet again to dip my hand into the pool of earphones availble on the market and fish out something new.
So a quick breakdown...
Pros: Good sound quality and liked the fact that the frequency range was unrivaled by some of the more expensive makes like Sennheiser whose frequency range is less.
Cons: Buds didn't sit too well in the ear canal and I tried swapping over the different plug sizes too, not particularly uncomfortable but could have fit better. Also, the obvious one, the life of the earphones, lasted under 3 months and only went through mild every day wear and tear.
Overall: Good sound quality and great price for some pretty average joes, but didn't last long!