My workroom has been through a few transformations, originally starting off as a bedroom, then bedroom cum workroom, until I finally decided that I would rather have the whole room. My DH has the garage and I have my workroom.
I'm fairly happy with how it has worked out, although I wish I had shopped around more before I got my desk. I saw a good one the other day in Ikea the glass insert would have made a great lightbox, not sure about the trestle legs, but there were plenty of other options to choose from.
If I need more room on the desk I can easily move things off, I have a fairly large amount of floor to lay things out, and there is plenty of storage in the wardrobe.