Well you are for sure going to need an interface of some sort. Those USB mics are great for things like podcasts and such. Basically anything where you don't need to monitor at the same time.
So that would be a total nightmare for any music with more than one instrument.
I would sell those USB mics, and get a cheap interface with a at least a mic preamp and and guitar DI. Then pick up a cheap MXL or other chinese condenser mic. The main reason is near zero latency monitoring.
Then use Reaper or Krystal with free plugs. Audition I hear is a bear to use for multi-track audio. Like Audacity, you can get the job done, but holy crap it is a lot of work.
Use Independence Free or a free drum sampler (check kvr.com) and program all the drums. Oh wait, you have already dropped $500+ or so on plugins with no hardware, so use those
For interfaces I have an Emu 0202 USB that I use in my office and am fairly happy with it. Clock stability could be better. But you can find them for $89. You can get an MXL 900 for $59 if you look hard enough. Or go used. Also check out the Line6 POD Studio's, they look great for the money.
In fact with the Emu stuff, you get quite a bundle of software. Cubase LE, Sonar LE, Amplitube LE. Basically enough stuff to get ideas down. Mix that with some free plugs, and monitors that you know, and I feel confident I could do some pretty sweet sounding release worthy demos. Commercial quality, well I would need better ears/skills first.
