My game room is our living room. We moved about a year ago and had the luxury of furnishing to suit us, so we wanted to create a living space that wasn't completely focused on gaming but that would make a good gaming space.
Ikea Expedit bookshelves turn out to be the perfect size for gaming books; they also work very well to display our glassware collection, which breaks up the monotony of the gaming books. There are also a lot of storage modules you can slide into the Expedits -- we have a couple of small drawer units and one cloth hanging file storage unit, which slides out for easy access. The miniature storage containers I mentioned here also fit nicely stacked in one Expedit space.
The table is also from Ikea, but there's no particular reason for that other than convenience of shopping. The key is that it's a good four person table most of the time, with a leaf to expand it out into something that'll work for a one-GM six-player group.
We use these little fold out trays you can get at Target as supplemental gaming tables -- when I'm GMing, I keep tokens and miniatures and notes there, so they don't clutter up the main table. They're kind of cheap construction but they're functional. Also good for eating in front of the TV.