In the backpacking/outdoor activity outerwear industry, it seems the new gee-whiz-bang material is eVent. This stuff is very breathable - so breathable, that they make dry bags with an eVent panel in the bottom, that you can squeeze the drybag and expel excess air, yet it is still waterproof. REI was one of the first outdoor stores to sell an eVent jacket. I remember reading employee reviews of the jacket a few years ago, that they found they had to wear an extra insulation layer, because the fabric was SO breathable, they felt colder in winter type activities. REI doesn't seem to have an eVent jacket anymore, but I found this one at EMS:
http://www.ems.com/product/index.jsp?productId=22225286&cp=3893527.11021492.41661566 Here is some info from the eVent website, and they do show the same pictures RichH showed:
http://eventfabrics.com/technology/
Most waterproof breathable fabric technologies don't breathe so much once water soaks into the supporting fabric. The exterior of all the jacket fabric is treated with a Durable Water Repellant (DWR) at the factory. This chemical is hyrdrophobic, and is what causes the water to bead up. Once the water soaks through the DWR, then the waterproof membrane just keeps the rain off you. Rubbing eventually wears out the DWR, and dirt traps down the chemical "fingers" that repel water. Cigarette smoke is the WORST, highly sticky and aerosolized, and it will kill a DWR finish straightaway.
Hmmm... now that I think of it, from working REI and knowing about the high tech fabrics, one thing is that when it's hot out, there isn't that temperature differential to drive the moisture out through the fabric, as the eVent website discusses. So, yeah, maybe eVent would be the best choice for tropical fabrics.
I have used a GoreTex XCR pullover spray jacket from Kokatat when kayaking and racing. It's a very thin fabric, with just an exposed GoreTex membrane on the inside. Seems to work pretty well.
I think there are a plethora of "waterproof/breathable" fabrics out there now, many of them are polyurethane. Many more since Gore's patents have expired. I've never been all that thrilled with the performance of a non-GoreTex shell for snow skiing, though I have to say that the one pair of non-breathable shell bib pants I bought for skiing were absolutely HORRIBLE. When I took them off, my legs were SOAKED. So, even "whatever" branded breathable materials (such as found on Columbia clothing) is FAR better than a non-breathable material.