Cubasis is not the most intuitive, but if you work through its learning curve, it's a good piece of software.
Unfortunately, as it is bundled, the pdf manual sucks, and there is no hard copy. You may find yourself getting into problems that you can't easily resolve.
Lots of people around here will recommend n-track, Cubase, Cool Edit Pro (now Adobe Audition), and others. I am leaning toward getting Audition, personally, as I am pleased with Cool Edit 2000.
mike