I have three:
17' rotating square
17 X 23
24 X 36
I use the largest one, on my cutting table, the most. I want to get a smaller one, maybe 12" square or so, to put next to the sewing maching. I do have the rotating one there right now, but rather have it available at the cutting table.
I might get the ironing/cutting one, instead of just a smaller square, for the sewing machine area, and to use for classes. On the other hand, having to get up to walk to the cutting table or the iron is "exercise", right? Maybe I should buy fabric with that money instead:D