Have a look at the Acer Aspire 9813, may not be hi speed for HD but duo processor AND the 20.1" screen makes life easier. Lots of connectivity incl. serial and paralled and DVI etc. Not a light weight but luggable.
I prefer a smaller screen size in exchange for better portability.
I purchased a refurb Dell D620 with a 15.4" display and 2.0Ghz Intel Core2Duo. Added 4GB of RAM, XP 64bit (yes it works 100% once I found the proper drivers) and added a 250GB drive for video editing via the drive tray that fits where the DVD burner usually resides. I don't typically burn DVD's in the field but can bring it with me as needed. I also have an external firewire laptop drive for audio as needed.