i recently bought myself a laptop - its great when im out on the road (especially when i find somewhere with an open network), around the house, or just curled up in bed.
however, i love my ultra-high res 19" monitor, and couldnt give it up, even for a 15.4" widescreen like the one on my laptop.
also couldnt give up my ergonomic keyboard, and my ultra-comfy mouse.
there are things that a laptop just cant do - and i really dont think i could affordably replace my much faster, much more powerful main machine on anything like the same budget.