I've mentioned this is another thread, but since it directly answers your question....
I've recently bought a KiSS DP-508 for exactly what you are describing.
http://www.kiss-technology.com/
Works great over 802.11g and there is a model without internal storage DP-500, but I wanted yet another location to backup all my music to that I could sync over night.
Also check out the forums here
http://www.gooddvdstuff.com/kissdvd/index.php
Most of the posts sound like the product is rubbish, but if you are ripping your own movies rather than downloading anything and everything it is a great product.
3 mates saw mine over Christmas and ordered one on the spot -
www.scan.co.uk has the best uk prices right now.
Phil