In reply to Victorine:
I'm a big fan of a decent, long roof. Though I don't actually see many people using them. I was a little let down that The Depot recently got rid of theirs. I love the one they have in Kendal.
What's the general consensus on topping out? Some walls (again, Kendal and I think one of the London walls I went to that's closed down now) have certain problems where you can top out. I found it a nice novelty but the regulars seemed to just hit the last grip and jump off, so it may be a waste.
Rokt in Brighouse have some 'interesting' layouts, have a look here:
http://www.rokt.co.uk/rokt_vt2/indoor-climbing-tour.htm
The "Roktagon" room (second and third down) is basically a free-standing structure that you can climb around, with a little seating area in one corner.
It's certainly unique but I think they have difficulty in setting it. Even when they get some "big name" setters in the problems either feel ridiculously difficult, really easy, or far too short. They are getting better though.
Even if it's not the best to climb on though it's certainly a draw to the centre.