Olympus 25mm f/1.8 Micro Four Thirds Lens
If you've been shooting photos with the Micro 4/3 system for any amount of time, there's a good chance you've already known about (or even owned) the Panasonic 25mm f/1.4 lens. After all, it is by far the most recommended one for M4/3 photographers.
But now there's a new competitor in town: the Olympus 25mm f/1.8 lens. It's smaller, it focuses faster, and at $399, it costs a considerable amount less than the $529 Panasonic. Admittedly, the photos it produces aren't quite as sharp as the ones you get from the Panasonic lens, but they're close enough that most people won't know the difference.
If you already own the Panasonic, you may not have reason to switch to the Olympus here, but for anyone else looking for a nice lens, the Olympus 25mm f/1.8 is a solid recommendation.
(For a more in-depth look at the lens and some sample shots, check out Steve Huff's review.)