I've just got the air max 1g that was on sale for 60 quid on nike website. I'd say they're pretty true to size. I wear a 10 in all my shoes and nike trainers and, with a pair of walking socks on, they fit perfectly.
I find its adidas that I have to go half a size up in generally.
To be clear - normally a 10, ordered a 10, they fit perfectly
