You need a monitor. Admittedly, what consoles are designed to do they do do very well. What they're not designed for they don't do. I doubt for instance that we'll ever see MS Word released for a console. Won't be seeing Photoshop or web design software either.
Consoles play games.
With a few small exceptions such as playing CDs or DVDs and reading some email, without making them quite a bit more expensive I can't see them having the capabilities of a computer. Now, all the bad stuff aside there are some good things about consoles. Some very good things actually. Consoles, due to the closed design of them are generally very reliable. I am however wondering about the Xbox with it's hard drive.