Same thing, there's really no perfect solution.

If it's cold out (below 50 degrees, including biking at 20 degrees fahrenheit), I have a full waterproof getup (it was expensive though):
Gore Gore-Tex helmet cover - http://www.amazon.com/Gore-Helmet-Co.../dp/B001ELIYZC
Shower's Pass Elite Jacket - http://www.showerspass.com/catalog/m...lite-21-jacket
Shower's Pass Waterproof Rain pants - they don't sell the model I have any more, I think this is their current offering - http://www.showerspass.com/catalog/m...ertible-2-pant
Gore Gore-Tex Cycling Gloves - Not sure which model, they're Goretex though, not windstopper, but they were also like $90
Gore Gore-Tex Shoe Covers - Note sure which model again, but they're goretex not windstopper. To be honest, this is probably one area where you could save some money buy getting something that's waterproof but not breathable.

Problem is - after all this expense, this getup still isn't any good if it's above 50 degrees. As other people have alluded to, even the most "breathable" raingear (which this is) will trap sweat inside it above 50 degrees and you'll end up just as soaking wet from sweat as you do from the rain.

Above 50 degrees, my best suggestion is to wear clothing that keeps you warm if it gets wet - most synthetic bike gear does, and anything made of wool does as well. You cannot keep your feet dry - fenders help keep your wheel from splashing on them, but if it's raining no matter what you put on your feet/shoes, water will run down your leg and into your shoe anyways. The only way to keep your feet totally dry is to wear full gear so no water runs down your body, and that's just to hot above 50 degrees.

Shower's Pass also makes a vest that's waterproof on the front for the 50-60 degrees stuff -
http://www.showerspass.com/catalog/closeout/tri-vest

Also, be sure to do research on the kind of tires you have - if they grip decently when it's wet. And the brake pads on your bike - some are much, much better in the wet than others. And as I mentioned, fenders help a lot if it *was* raining and there's water on the road but it's not raining any more. And they help keep road grime from getting thrown up onto you in any conditions - rain is just water and will dry, but road grime is pretty nasty to get rid of.

The one other thing I've heard of is a "rain cape" - you look kind of silly, but it's open on the bottom (for airflow, and you need fenders for it to be effective) but waterproof on the top so it keeps the rain off of you.