if you're serious about recording and mixing, i suggest you forget about the 'cheap' solutions like m-audio (don't get me wrong, it's a good brand, but not at audiocards). you should go for an mbox (the first one, with focusrite pre-amps) which give you the option to run protools Le, 'the industry standard'. you can find these on ebay for like 200usd, which is a great investment imo. you could check around for an emu card or whatever, i don't really know what's playin these days.
check your microphones aswell, as good (or bad) as your mic pre-amps might be, they have a significant role in the overall sound which is plain logical.
as far monitors, the only way to decide which set you want is to listen to them at a store or whatever. do listen to your own music on them, listen to what suits you the best, this is the ONLY way!
everyone's after a set of monitors that have a flat freq response, but theoritically this is impossible, as much as the manufacturers claim this, the acoustics of your control room also play a vital role in the overal sound ofcourse.
yamaha makes 'decent' low budget (as far as this can be achieved
), i don't really know what else is good, low-budget-wise.