what's the budget?
DK and I tend to give each other "experience" gifts
*dinner at a really nice restaurant (e.g. took him to Morimoto for chef's tasting menu+drink pairings)
pro sports tickets (+ food/drinks at the game + travel, if necessary - he planned a trip to Anaheim for a hockey game, last January - too bad they ended up striking.)
long weekend trip (I'm taking him to San Antonio for his birthday, in a few weeks - shhh it's a surprise)
"zookeeper for a day" - he planned this one for me at the Camden aquarium - behind the scenes tour, animal interaction, etc. (f you're near the Sea World in FL, they do something like this - I've been looking into it for the SA trip)
amusement park day trip (pre-kid)
You could also go on interests/hobbies
DK is into fish/aquariums so I've considered getting him a large tank setup (like 100+gal)
I got him a homebrew kit for Valentine's day that was a big hit.