Rain capes and a rain hat are the way to go. I replaced the rain cape I bought in Germany (for under $10) with a J&G rain cape and have been pretty happy with it.

If you want to go for gore-tex or other waterproof breathable fabrics, there are a couple of things to keep in mind.

1. The efficiency of the moisture transporting membrane increases as the temperature difference between the inside and the outside of the fabric increases. Since it's pretty much always body temperature inside the clothing, they work much better when it is 30 out then they do when it is 70 out. (Gore-tex was originally developed for mountaineering, where not only did it tend to be pretty cold, but the lower atmosphere at high altitudes probably helped some, too.)

2. No waterproof breathable membrane can really keep up when you are engaging in strenuous activity. However, pit zips and other means of ventilation do help a lot. (They also help with non-breathable waterproofs, but since those have become the "budget choice," it's hard to find any with good ventilation.).

3. If you give up a little bit of waterproofness, you can get a lot more breathability.