Shure SM58LC Shure SM58 Vocal Microphone $99.95 [amazon]
Mackie Onyx 1220 12-Channel Mixer $529.99 [amazon]
Adobe Audition 2.0 $349.00 [amazon]
If I just got the microphone, I could buy an XLR adaptor that would cost about $10-$20 that could plug into the microphone port in my computer.
Adobe Audition is only optional if I can get free software that works as well, and while the mixer is a little much, it will pretty much make all of my recording problems go away forever.