I have a pretty economy 7720z as my desktop replacement for a while.
it's 17 inch , and can do all the work tasks fine. Miss not being able to play games on it though, so forked out around £400 to rig up my desktop with some higher end parts.
Realised if I had spent the £340 (money I spent on laptop) add another £400 (money I spent on upgrading the desktop), I would end up with £740 and enough money to buy a good latop with gfx card.