Another vote for 5x7 as a wonderful contact printing size. It also makes for a reasonably compact traveling camera. I took mine to Argentina with me and came back with some great stuff. You can also double and triple up to make diptychs and panoramics. Since I started shooting larger format negatives, I've gone over almost exclusively to platinum/palladium printing. Once you get your method down, doing pt/pd is not really that much more expensive, since you don't burn/dodge with it. Usually the first print is a good working print, and often is also the final print.