would be good to know what s/he already has , interests and what equipment s/he uses...... if someone were to spend £25 on a "how to photo a wedding DVD" for me, it would be on the for sale section here within the hour!!!!
Memory is always a safe bet, or a voucher for printing at Photobox etc? or depending on make of camera a voucher for Digital depot / SRS etc (if they do them)
Subscription to camera mag - no actually forget that one.
I know your intentions are good, but as the receiver of many crap golf presents over the years (Tees in a plastic xmas tree, and personalised golf ball markers - thanks but my marker pen does that quite well!)
Can you ask his/her "significant other" if there is anything she/he wants / needs?