I use the Patagonia Houdini and I'm very happy with it. It's good for light rain and bug protection. I even sleep in it. When not needed, it rolls up to the size of a tennis ball. It's also surprisingly durable considering how thin the fabric is. I always take it with me, day hikes or overnights, winter and summer, deserts or mountains. I even use it for kayaking and bike riding. It's one of my favorite pieces of gear.

Its main drawback is the price. Ouch. But if you're not in a hurry they often go on sale. I snagged mine for half price.