>>1145111>pedals If you want cage pedals, mks is good.
If you want flat pedals, i recommend some higher quality plastic BMX pedals with pins. Plastic commuter pedals are usually quite low quality, and metal pedals are gratuitously strong and less pleasant to use because they scratch your shins etc.
If you want clipless (and clipless are really fantastic), i would suggest you visit a few local shops and see if you can find any shoes on special that fit you really well. Fit is absolutely paramount, and you shouldn't order online. Lighter is generally better, and so is a carbon sole as opposed to a fibreglass sole, but how comfortable and well they fit they are is no 1.
Spd-sl is shimano road & spd is shimano mtb. Both are good for a road bike. Spd is much much easier to walk in. Spd-sl gives less hotspots on your foot, lighter shoes, more cleat adjustment (maybe a bad thing if you aren't getting a fit), and generally stiffer shoes, plus they look more pro on a road bike. All those benefits are really quite marginal though, for being shit to walk in, but if you find road shoes that fit you better, i'd get them.
For the pedals if you go clipless, get shimano and just spend what you want to spend.