I always think that xmas should not be abour things you need but things you want!
I was in a similar boat and couldnt think of what to get mine and his parents had already got us a x box 360 as a joint gift so what to get.....
ended up getting him lots of gifts at the 40-50 quid mark. A mixture of things he would like and things that meant stuff to us.
Eg got him dvd set of series he likes, a few cds, 2 games he liked for the x box, buckaroo (an in joke), a beer making machine (half price on www.iwoot.com), a zorbing experience, a topr from the shop he buys from that i hate to show him i love him the way he is, and a room in the hotel we stayed in when we met.
just a few ideas and hope they help.