Nothing wrong with that one! Also have a look at Asus and Acer laptops, there are several special offers going around right now! I'm editing in Reaper on an Acer with 8GB RAM, dual core thing that just cost me $430 a couple of weeks back and I am perfectly happy with it. OK, I won't be doing any hi-def videos on it, but it does the job of being a handy little audio box and the 64-bit version of Reaper is nice and fast. Amazon and Amazon feedback is your friend here!

Laptop? MacBook Pro. Everything else is less. Apple hardware still wins for price/performance in laptops. Supports all flavors of OS.

one other requirement... quiet