Billiard tables tend to be a bit on the massive side. Plus, you'll be in competition with all the billiard players who wouldn't mind having their own table.

OTOH, you could do worse than build a [link=http://home.mindspring.com/~the-plumber/PhotoAlbums/Torsion%20Box%20Building%20Table/index.htm]torsion box building table[/link], which can be taken down and stored upright against a wall if you ever need to recoup floor space.