Living in the South Eastern US, we get a lot of the afternoon heavy rain showers and occasional tropical storm or hurricane.
I'm a year 'round rider and have Frogg Toggs for the Summer months; they're light weight and breathable and great for shorter commutes and brief down pours. I recently had an experience with them on nearly all day on a ride and experienced some soak-through on the side most impacted by the driving rain and winds. It wasn't much, but enough to notice. Fortunatley I was 10 miles from home and just didn't care at that point anyway. In my opinion, they're a good choice and aquired cheap enough. I paid $50 (US) at Cycle Gear for my set, and even bought a set for the wife who swears by them.
For heavier rains and extended riding, I purchased a rain suit from J&P Cyles for about the same $$ and have owned it for a couple of years now. It's never let rain through and has passed the test of time easily. It's only fault from my point of view is it's HOT to wear is the weather is temperate.
An added consideration is waterproof boots, or boot covers. I picked a set of the Tour Master Deluxe Rain Overboots for $19 from these guys:
http://www.motorcyclegiant.com/Tour-...9-0105-03x.htm
and paid $7 shipping, by far the cheapest I've found. These work fantastic and are popular for a reason.
Gloves are another issue and something I'll leave to your personal taste.