I'm currently doing plans for an extension to my own house (seeing as I've managed to finish all my mate's plans

) and yes you guessed it - I'm gonna build in a HT room.
The plan of the room at present is 2.8m x 2.8m which isn't huge but I reckon I can fit everything in without any problems - what I'd like to know is would I get any real benefits from making it slightly bigger? I'm a bit pushed for space but I could pinch an extra foot in each direction if I wanted to...
thanks in advance.