Shimano SPD-SL pedals with Shimano TR31 shoes for me. The straps on the shoes are reversed compared to many other shoes but this aids in safety when dismounting while leaving shoes on pedals. The straps are pulled to the outside away from crank arms and chain.
I like my clipless pedals. It takes a few rides to practice snapping in and out but seems WAY easier than clipping and unclipping, since you can do it without reaching down to your foot. The disadvantage is that you have to change shoes in T2.
I would definitely use cycling shoes with pedals you clip into (calling them clipless confuses me). Me personally I have used a pair of Forte shoes with SPD clips. Not the fanciest shoes but they have gotten me through alot. If you've never used clipless/clip pedals before, a little forewarning you will fall until you get used to them. At least a few times.
Also an important note about taking your feet out of your shoes prior to T2. If you practice it and you're good at it by all means go for it. I have volunteered at races and let me tell you that lots of people will slip and fall or waste time trying to get their foot out. If you cannot do it quickly you'll save more time overall simply running in your cycling shoes to the changing tent. IMHO.