Laptop vs desktop? I prefer desktop personally .. well, to be honest? I actually loathe laptop! cramped keyboard, tiny screen, useless touchpads .. you get the picture
As for specs - since I don't think you play games, anything on the shelves of an electronics store will do really. Basically go to the store, and tell the clerk the features you want most: integrated webcam (integrated might be available only on laptop - but some kits come with a clip on cam that goes on the monitor), blu ray player, micrphone, ya da ya da ya da and he'll show you what they have with those features.
As for actual spec .. everything these days is more than powerful enough, and costs nowhere near 1,000$ (unless you want gaming - gaming is always the defining point).
Things to look out for? Dual core processor is pretty standard these days, 4GB+ RAM memory wouldn't hurt, 500GB+ hard drive won't hurt either.
The rest is all technobabble.
EDIT:
Oh wait, if you are going for blu ray, you might want to make sure the system has an HDMI port for future proofing - or if you already have a HDTV to go with the bluray.
