Something like the stuff they have on Threadless link
I find some of the graphics funny and/or cool and I used to express myself by wearing them. But now that I'm in my mid-20s, I don't think graphic tees are flattering anymore. Especially since I've been wearing more blouses and skirts and dresses now, those just don't look good anyway with graphic tees.
I think they're OK on occasion, but that you need to start wearing them in fewer settings in your mid-20's (and older). I like wearing plain, well fitted tees still, even in my early 30's. But I pair them with cool/funky jewelry or a cardigan/jacket. But still not all the time. I think you're moving towards a nice wardrobe balance. Think of some new accessories or color combos that still make you feel like you're you.