Actually Scott I was goign to say that same thing...
Nobody at home (ok very few) would have any need whatsoever with a gigabit NIC.
You would also have to have a gigabit switch .. if not you're going to get negotiated down to 100 anyways...
Not to mention unless you're CONSTANTLY moving LAAARGE files.. its generally worthless for home use

If you move an OS image once every 6 months.. yeah thats one large file, but after that what good does itdo?
Your game won't run any faster on LAN's either.