This is a kind of crappy picture of one of the gaming tables I built in my cellar. While there is enough space to move around it while gaming, there wasn't enough space to stand back and take a decent picture.
The top gaming surface is 4ft x 8ft. The tabletop underneath it is 5ft x 8ft. The storage shelf on the bottom is 4ft x 8ft.
Plenty of room for miniatures, books, dice, drinks, templates, etc... on the tabletop, while leaving the gaming surface entirely for gaming.