Another useful tip: whether you've been in MAD or the surrounding countryside during summer months, chances are you'll arrive feeling a bit sweaty (ie hope I'm not sitting next to you on the way back to Blighty).
There are very pleasant shower suites (mainly geared towards those flying long haul on from MAD) open to all; just present your BP at the reception desk and ask for a key.
Then relax, and as others have observed, enjoy all that's on offer. This, based on tradition, is a very un-IB-like experience.
And kudos to Richard Rogers for the airport design. Norman Foster should be shot for homogenising airports around the world. The Good Lord Lefty and co-owner of a rather godo (if expensive) restaurant in Hammermith should feel rightly proud of a design which combines the best (if somewhat dated) bits of the Lloyds Building with local influences (terracotta etc).
The whole place is a dream, I'd just hate to arrive at the check-in area with little time to catch a flight...
Adios.