I tend to agree that the Zoom might come up short. It kinda depends on what you want.
Under $300 mics...I'd debate a bit with the previous poster. A pair of Avantone CK1's can be purchased for around $300 new and I think I saw a pair go used recently on the Yard Sale for just over $200. These mics kick butt soundwise for that price. Search the Live Music Archive for samples. You'll like what you hear. Combine those with the R-09 that is currently in the YS for I think $230 and you've got a pretty darn nice sounding unit for under $500. You'd definitely need cables and probably would want something between the mics and the recorder (preamp with phantom power).
Another under $300 mic option would be AT-853's either with or without a battery box. These mics are discussed every several days on this site and run less than $200 new from
www.soundprofessionals.com depending on configuration. Same thing...listen to archive for some sound samples. I think there is some AT-853 gear currently for sale on the YS.
Church audio gear would also be a reasonable option...look in the retail forum (just below the Yard Sale on the home page) for Chris's (Chris Church of Church Audio) specials that he runs all the time. There are one or two used sets of Church gear (mics and 9100 preamp) currently for sale on the YS.
All of these would be options that approach your budget and provide a reasonable sound combination.
BTW, I can't really address recording directly to computer. I think most people on this list don't consider it simply because we open record in the club environment and bringing a bulky laptop out for people to spill their beers into and burn with their cigs isn't an option since there are fairly inexpensive options for digital recorders. I've seen plenty of SBD connections directly feeding into a laptop at the SBD though, so I know it's done. Most on this list though prefer the live recording over the SBD because the SBD mix is often off and SBDs can be pretty sterile and uninspiring.