Sarah, I ditto everything Ana said. Here are some additional thoughts and experiences for what they are worth:
Makeup: I am like Angie; I wear a little bit almost every day. Not a lot, but a little. And with short hair, like Ana, I feel I need it a bit more. My absolute necessities? A bit of lip gloss or at least lip balm (the latter is probably okay in your book, I'd guess); my concealing cream for my inherited undereye circles (probably not a necessity for you); eyebrow pencil. A couple of times a year I splurge and have my eyebrows tinted but in between times I resort to the pencil.
The pencil I use, if you want to try it out, is nothing special, expensive, or fancy. It is Revlon's Brow Fantasy Pencil and Gel in Dark Blonde 104. In fact, if your brows are thick you might be able to use the gel alone (sort of like mascara for your eyebrows). You just brush it on and go. You could try this in the privacy of your own home and see how you feel about a slightly darker brow. The degree of darkness is very controllable; I put a bit on and sort of wipe it off so it's a bit lighter but still enough to frame the eyes. HUGE improvement; check out Julie's brow thread from the other day to see: http://youlookfab.com/welookfa.....ow-edition
It's not like wearing coloured makeup. It's a very different thing than blush or coloured eyeliner. It doesn't feel "made up" or "girly." It just sort of finishes the face and gives the features the emphasis they deserve. When you are very low contrast, it adds expression to your face.
Upkeep: In my experience, short hair requires LESS upkeep (for me, personally) than long. Yes, I need it cut more frequently. But not that much more often. When my hair was longer I got it trimmed every 2 months; now I go every six weeks to 2 months. If I wait the full 2 months it does look a bit ragged, but I can usually deal with it by using a bit of product. I know you said you don't use product, but a good stylist could show you some that might be helpful.
I also spend a lot less time styling it (or trying to style it). My hair is air dried, unless I'm in a huge rush. I wash it about twice a week. Many mornings, I just wake up, finger comb, and go. Other days I might run the straightening iron through my bangs (takes 5 seconds). That depends a bit on how I've slept on it and what the weather is like. Humidity can make it look a bit different. I sometimes use product but that is more to achieve a slightly different look—more piecey or textured or punky. FWIW, my hair is very thick (VERY); fine textured, mostly straight but with a slight wave.
I think you'd look super in short hair and it could fit very well with your style persona. So I'm all for a cut!