Shoutbox

I believe any Dell with 17" will be powerful enough for your requirements for a very reasonable price.
Except for the weight, but in this case I believe any model you find will be a bit heavy. If you want something light, you should get one with a smaller screen.
I'd not recommend HP, I've had too many bad situations with them in the past few years; Dell always seemed good for me, never had trouble; Asus and Vaio seem pretty decent and high quality, but I've never really used any of them.