A lot of folks use Cool Edit. I haven't, but that doesn't mean anything. The Behringer units you mentioned get good reviews- I like Behringer stuff. Hard to beat for the price.
The Sound Blaster is probably the weak link in your chain. The are pretty generic, made for genral computer use. An MAudio 2496 card will give you better quality.
Once you record your vocals, the 2 most common things to do are to add compression and reverb. These would be effects software plugins that work with Cool Edit. Compression will probably help a lot for the genre of music you're doing. I'm not sure, but I think Cool Edit uses DirectX type plug ins. Check on that, though......