Hmmm, well if you want to go sweet, you could make a montage of all the photos of eachother you’ve got and frame it for him… he might find that a bit twee though!
You could make him his favourite meal, or organise a night with his favourite drink and nibbles and watch all HIS favourite films (without moaning about how rubbish they are)...
You could make a home vid where you go to all your favourite places together and say why they’re special to you two (eg, this is where we first met/kissed/saw a film etc etc etc)...
Hmmm, hope these aren’t too lame!