A proper thank you

I have a wonderful boyfriend. We celebrated our three-year anniversary this week, and he didn't balk when I had to reschedule our plans (still sick) he arranged for dinner months ago -- at L20 no less -- that we had been anxiously waiting for. His gift to me was a full-day of spa treatments at The Peninsula, arguably one of the nicest hotels in Chicago, because he knows I've had a rough go lately and knew it would be special.

The gifts are thoughtful, touching and more than I could ever expect or want. What means the most though is that he's there for me, saying and doing just the right things, when I'm at my lowest points: during difficult family issues, like cancer; the death of someone near and dear; an incredibly stressful stretch at work (I'm doing great, but the work situation is unhealthy); and The Great Sickness of 2010. He's run to the store for Gatorade and Kleenex; called his friends to bring me food when he was out of town for a funeral and I could barely get out of bed; and refused to let me help clean up or do anything, really, when I've been well enough to go to work but miserable enough to want to go to bed as soon as I get home. I've known many men who wouldn't go nearly as far for their partners as Brian does for me.

I want to get him a little something or do something for him thank him for being him. I want it to be sentimental but not top of mind. Not over the top, but more than a sincere card. And although food is one of our favorite things to explore together, I want to think beyond that.

If you have any ideas, my ears are open. Thanks. :)

Update: I've fielded the suggestions of truffles (as in the mushrooms), cooking him dinner and a heart-shaped cake. I really like the cake idea! The other ideas are great, but the timing's a bit off: I recently bought him truffle oil (and we received it as a gift, too) and we cook each other dinner frequently. I like the suggestions tho! Helps me think.