God I can't imagine running Handbrake or FlaskMPEG or VirtualDUB on anything BUT a desktop. I do all of my Photoshopping on my desktop and all of my Premiere work, also. I used a relatively modern laptop a while back, and it just couldn't hold a candle. It was a difference of about an hour in ,y h.264 Handbrake stuff, about a half-hour with DivX and like 10sec/filter in gIMP/Photoshop. Premiere is snappy almost-instantaneous with my cuts/effects, and it was lethargic and "hour-glassy" on the laptop. And on a separate note, I've yet to run across an appreciable DX10 laptop. Some of them are able to do DX9 content appreciably, and most can do DX10 at like 1280x, but I play games at 1650x1080, and no laptop I've been on save a few multi-thousand books compare. And lordy, I see my boss running a Virtual Machine on his laptop and I couldn't handle how painfully slow it is.
So, the desktop has it's place, the same place it always had: CPU-intensive tasks that need high-heat/high-energy parts and GPU-intensive apps that need high-draw/large-scale parts. For "basic" things like ripping CDs, AIM, Office-oriented tasks, the laptop will dominate.