In reply to ianstevens:
I've got Thermarest Prolite (short - 120cm long) mat. So far, I have used it only as 3 season mat and it worked very well. It might be too cold for your needs, so I am not going to continue about it.
The other option I was looking for was Thermarest Z-lite Sol sleeping pad. It is supposed to be more durable (especially if you bivi a lot) and is very lightweight. However, it is not as small as self inflating mats.
No experience about NeoAir mats as I couldn't really afford one.
What I know very well is that sleeping mat is a must even in summer! I used to travel around Europe with a poncho, 3mm sleeping mat and 550g sleeping bag (extreme temperature is +2C) set-up, but in Scotland that does not work very well.