Can a notebook serve as a replacement to your current desktop system? Yes and no. It all depends on what you use your current desktop for. If your desktop serves as an e-mail/web machine for only a relatively light amount of work, then yes. If you like to play games or do high-end type of work, then probably not. If you have a need for the type of portability a notebook provides, then the answer is definitely yes, keeping in mind that you will pay the premium. $2000 can get you a decently equipped notebook, but it can get you a very fast desktop if you shop around a little bit. Which goes to show you, integration and speed don't go very well together.
The HP Pavilion is a decent notebook for a decent price. I wouldn't have too much problem recommending to someone else. The only thing I had a big problem with was HP's tech support. First of all, it's not toll-free and the hold times are a bit on the ridiculous side. Hope you don't mind waiting on-hold. I never actually talked to them because I got sick and tired of waiting. I don't know about their quality of support so I can't make a judgement on that.