I removed my WD 640GB & replaced it with a seagate 1.5TB. I would like to get the use of both drives but due to potential heat & space issues I really don't want to put both drives in the HTPC case. I was considering puting the 640GB back in the HTPC & having the 1.5Tb in an external enclosure. However, I don't want this enclosure sitting out next to the HTPC.

What are my options, would I be better looking at NAS? Any thoughts?