I'm cheap, so I like using my issued gear. I have had tremendous luck with my issued ECWCS Gen III Gortex jacket and pants. I've had 1 set for 7 years now, and just starting on my next set (thanks DoD for changing camo patterns and making me rebuy all my nice gear). I try not to be outside in torrential downpours, but they have done the trick as a super nice outer layer and just by themselves as a rain jacket. You can get good deals on the ABU and ACU patterns right now but OCP stuff is going to be a bit pricey for what it is... They are the best sub $100 jacket you can buy, and while they are not a good $300 rain jacket, they can be had for $70 and below so...mDon't mess with Gen I or II stuff, you want the double layer Gortex Gen III, level 6 stuff. Coupled with the fleece and a base layers it's also a dang good cold weather system. Sadly you won't really find them in non-military camo, and running around in an ACU or ABU rain parka isn't exactly a fashion statement.
There are some lightweight options out there (called APECS), while they will look somewhat similar in pictures they are much lighter and more designed for warm weather wear (IMO). I have a set as well, they are good for rain but I much prefer the ECWCS shell for colder weather. That said, the APECS is quieter, but also more expensive and harder to find in the mil-surp stores. To me, the ECWCS seems more durable to me as well. I can't say I've worn out an APECs set or anything, but the ECWCS sets are pretty bullet proof and just overall heavier duty.