From my experience, I would say it depends on how fast you want to slice and how often you want to sharpen your knives! The harder the board, the faster you'll slice, but you'll sharpen more often. The hardest, fastest board I've ever used was bamboo. The slowest probably end grain maple. My Aunt's are end grain maple, and for them, (old and uncoordinated) that's a good thing. I don't want to cut 100 pounds of vegetables on them. I have laminated maple, which is still pretty slow. Plastic, which is still slow. Oak, olive wood, and bamboo are faster. I like bamboo. No drag. Your knives will get dull faster though. For bacteria, I cut meats on their own plastic board. I wash boards regularly. My interesting exception is my big board for rolling dough. Pizza and pasta dough have eggs in them, but I never wash my dough rolling board. Dough won't stick as bad if I don't wash it. Kind of like a cast iron pan!
