The thing about the non-USB mic (Did I really pay $40 more for mine that I could have!? GRAGH!) is that it uses XLR, which your sound card doesn't support. You can get around that by buying an XLR to 1/4" converter, though, because it looks like your soundcard has a 1/4" mic jack. If it doesn't, then it's definitely not worth getting the XLR version unless you also plan on investing in an audio interface. You'll lose so much audio quality going from XLR to 1/4" to 1/8" that it's not even worth buying more than a shitty $20 USB dynamic.
The only problem with that is that I'm not sure how good your soundcard's preamp is, or if it even has one. On top of that, because the AT2020 is a condenser mic, your soundcard might not supply phantom power. If that's a problem, then something like this would be a good investment:
http://www.musiciansfriend.com/pro-audi ... mic-preampFor the most part, though, an XLR mic is the way to go, if you can make that work. If you decide to upgrade and get a real audio interface, then the XLR mic will stay with you, while all your USB mics will lag behind.
The AT2020's a good all-around condenser. It's really bright, but that's great for a lot of acoustic instruments and vocals. Another one you might want to look into is the Shure SM57 -- it's a dynamic mic, so you don't have to worry about phantom power. I have next to no experience with the SM57, though, so I can't really say much about how it sounds. It's just the go-to all-around good mic that most people recommend.