I've been trying to determine which print sizes I prefer. In the darkroom I usually print 8×10, mostly because it's the largest convenient size. Lately I've been making quite a few 5×7 prints and I'm finding I prefer them to the 8x10s. An 8×10 photo is just a little too big to hold, and just a little too small to hang.
I've also made a few 13×19″ digital prints and it made me realize that for hanging, bigger is better.
So, for now I’m going to stick with 5x7s for everything except the prints I intend to hang. For those, I’ll go as big as possible.