A lot depends on temperature. My commute can take 50-55 minutes on a rainy & windy day including stop lights. I have rain pants for legs/lower body if it's a really cold rain; leg warmers for in-between, and my legs just get wet if it's mid-upper 60s (F) or above. Hi tech rain jackets (both Endura, one lighterweight/ultra packable) for upper body. Again, a balance between staying dry, comfort, and ventilation. I normally wear a head sweat under my helmet, switching to a SealSkinz beanie under my helmet if it's a cooler day. Various gloves for hands, again depends on the temps.

The trickiest part for me are my feet - I have waterproof cycling boots (Lake), but when water splashes in over the tops, my feet get and stay wet,the shoes take forever to dry out at work even with aggressive stuffing and changing newsprint. I recently purchased waterproof SealSkinz socks. Based on a few rainy commutes - they work. I deliberately wore ventilated shoes; feet stayed dry and I didn't mind that the shoes didn't dry out completely before the ride home. They make several styles including one with grippers on the tops that are claimed to be completely waterproof (they show a photo of someone standing in water over the sock tops). For the rest of my stuff, panniers or backapack with rian cover and anything that can't get wet is in a big ziplock bag. I also keep a change of shorts & socks at work just in case I get soaked in the morning and want something dry for the ride home.