In reply to kluz:
i use the £10 blow up one from Argos,
stil l good after 4 trips to alps , couple of scottish winter wild camps, small camp outs with kids, near ice axes, crampons, stoves
no punctures, strong, weighs f*ck all, rolls up small, easy to blow up above all comfortable
cant go wrong
http://www.argos.co.uk/static/Product/partNumber/0198149/c_1/1|category_roo...
however it gets slated on the reviews, wonder what their usign theirs for?