We used to game quite a bit on tables of 6ft x 12ft (~2m x 4m), but this would force players to walk around to the enemy side of the table as troops or ships or airplanes went across the center line. One of my friends still sets up a 6ft x 8ft table in that space, but it is more cramped now that there is a bar with beer taps on one side. It's still a reach to the other side of the table.
A 5ft x 9ft table would be really great. We would not have to walk around the table quite so much, or take so many chances at straining our backs. I may try to get my brother to give up his ping pong table at some point, because the kids don't use it anymore.