What's are some good lightweight jackets for hiking and biking?

A: All comes down to whether you want water-resistant or something close to water-proof. The Dragonfly is, as you note, a light water-resistant shell. Light rain, fine—for a while, Anything more than that, and you're apt to get damp. Patagonia stuff tends to be expensive but is almost always worth the expense because the construction, fit, and detailing always are good. Still, for something that's not waterproof, $135 is a bit dear.

A favorite lightweight/waterproof piece for a lot of folks is the Marmot Precip. It weighs 12 ounces—still very light—and is genuinely waterproof, yet pretty breathable. And...only $99. Lowe Alpine's Adrenalin Fusion ($70) is competitive with the Precip, although its liner isn't quite as nice. For something very trim, Pearl Izumi's Channel Jacket ($199) uses a proprietary waterproof-breathable fabric and vents beautifully. Or, Sierra Designs offers the lightweight Tempest ($99), which also is waterproof and breathable.

Other than that, there are lots of pieces in that $100 category that offer good but not perfect rain protection, a la the Dragonfly. One good one: The Arc'Teryx Hybrid Jacket ($135) weighs just nine ounces and offers a bit more durability than the Dragonfly.