I got Michelin Country Rock 26x1.75 for my daughter's bike. She's only put about 20 miles on them so far, but they look pretty decent -- not too heavy, semi-slick but with enough tread for dirt or gravel paths. They were around $17. Thick tread seems to be the only protection against flats, but that can be pretty effective. The reviews I found were mostly good.

On my Cross Check, I've been using Maxxis Re-Fuse, which are pretty easy to find in the $25-30 range. They roll really well. Reviews indicate that they have great flat protection but that at some point the tread starts to flake off (though apparently the flat protection continues after that). I've put around 600 miles on them with no flats or sign of tread wear or flaking.