I'm not a mani/pedi person, either, but due to shoulder, back, neck, elbow and wrist issues from tennis, I have become a big fan of massage. Of course, that's not necessarily a reward; it doesn't always feel good! Otherwise:
Books (what about healthy cookbooks?)
Music (downloads for my iPod)
Plants (to put in the yard)
Clothes (mostly exercise-wear; hopefully brave enough for a bikini soon)
Maybe something along the lines of what you like to do for exercise; like I would get a new tennis bag or hat or skirt, whereas you could look at some backpacking/hiking gear.
I'm not really into shoes, jewelry, or purses, but I love sandals in the summer, so that could go on my list occasionally.
And now that you don't have to be perfect, you can be good.