Typically, when we play at my place, I run/play games on my dining room table with the leaf in. So it's about 3'8" x 6'6" long. It's a tad long for my tastes, but it easily sits up to 8 people with lots of elbow room or 10 with a bit less room.
Seeing as my groups seldom get over five players and me, it's a bit big.