Platform Pedals - you can get grippier platform pedals for rain. If you're willing to spend some money, you can even get ones with pins that stick out of them for grip in all conditions.
Toe Clips - I personally am not a fan, but if you're used to them and like them they have some advantages. While I feel they don't add that extra efficiency like clipless, they do let you ride in a wide variety of shoes that are as comfortable as you can possibly find to walk around in.
"Clipless" - max efficiency with a shoe with a stiff sole, but they have the drawbacks you mentioned. For one you have to wear special shoes. For another, the special shoes aren't terribly comfortable to walk around in - I wouldn't want to walk around off the bike all day in them. You can get shoes that are better to walk around in that have a less stiff sole, but I've never liked them - felt like the cleat squirms a little to me. I dunno, maybe I'll try them again some time.
I personally use the $90 Specialized mtn shoes on my of my bikes (except the main road bike) because I've learned they fit my foot the best for riding. I'm considering getting a pair of the carbon versions.
For pedals, I use the Time ROC Atac for the following reason -
1. Float - plenty of float (vs Shimano SPD's I had before) but without feeling horribly loosy goosy (like the Eggbeaters did). If I switched the cleat I could have more, but I don't need it.
2. Clogging - Have a reputation for never getting jammed up with dirt, mud, etc (same as Eggbeaters, but spd's reputedly not as good)
3. Noise - "click click" noise when walking around - better than my Shimano spd's were, on par with Eggbeaters - they're usually quite, sometimes make a slight noise on hard concrete, but no other surfaces. Best I know of.
4. Durability - reputation for lasting a long time, with no maintenance (spd's have similar reputation, eggbeaters have a pretty bad reputation though they just released new versions which are supposed to fix that).
5. Feel the Click In - I can tell when I get clicked into the pedal, or out, just by feel. Eggbeaters didn't have this at all, if my recollection is correct I think it's better than the Shimano SPD's as well.
6. Easy to clip in/out - most pedals are. The Time Control Z's I bought required more force to clip out than the ROC's.
Platform pedals belong on anything categorized as a "bike" if you want to use them.