If MSeries were still on the forum, he'd say Looks or SPD-SLs, cos you're going for a bike ride, not for a walk
When newer cyclists in my circle ask me this, I generally tell them to go for SPDs, cos they're cheap and seem to work for the majority, even though I hated them myself.
Currently, I'm Time Atacs on everything. The pedals last yonks, the cleats not so much (but it's surprising how much they work even when looking completely knackered). I used Crank Brothers for a while, and for the same reason as Atacs - they work much better with my knees. But the Crank Brothers pedals didn't last long, were comparatively expensive, and though you can get the rebuild kit and that wasn't a complicated job, it just worked out too expensive.
I started off on Looks, and used them for a while, and probably still would, but since I don't drive and a lot of my riding is utility riding involving walking at the end, two-bolt designs make more sense.
I don't mind flats, and when my Crank Brothers pedals gave out in India, I got some cheap flats and rode out the rest of the tour on those, but comfort is the main factor for me in having clipless pedals. I've ridden 100-mile rides on rat-traps with gym shoes, and my feet were a bit achey by the end.