Clips on everything.. Including the Dirt jump and BMX bikes. Once you get used to unclipping, it becomes second nature and there is no issues. I have done a few dozen backflips in my dirt jump days, and all of them were clipped in, and I was able to throw flips and 360s away comfortably and still be able to get away from the bike while running clipless setups..
One of my favorite moves on the DH bike is doing nac nacs while running clips. You unclip as you leave the jump, drape the leg over the rear wheel and then bring everything back and you will clip back in right as you land! Good fun! Also suicide no handers are so much easier with clips.. You can push the bike away from you and then pull it back using your feet instead of having to pinch with the knees.. Kinda cheating, but makes it easy to throw huge no handers.
The one bike I actually would consider tossing flats on is the Levo.. I use it so much for running to around town to the store or post office that the SPDs do get annoying when I can't be bothered to put my real shoes on.. And all the platforms that clip into SPDs to make them a "regular" pedal suck..