Best Mirrorless Rangefinder-style
Sony's NEX series usually dominates the mirrorless camera category - a big step up in image quality from point-and-shoot cameras (and with interchangeable lenses), but less bulky than SLRs. The newly launched 16-megapixel Sony NEX-6 model continues to fend off would-be competitors with full HD video recording, sophisticated hybrid autofocus, APS-C sensor and, because all the cool kids are doing it, WiFi.
$999.99 with 16-50mm OSS lens
Also consider: Panasonic GX1 with 14mm F2.5 lens $749.99
Best Mirrorless SLR-style
Olympus, one of the originators of the Micro Four Thirds system, was an early trailblazer for mirrorless-style cameras. Though that system, which puts the image sensor of DSLRs into smaller bodies, is now almost standard, Olympus continues to innovate. The new Olympus Pen E-PL5 is great for versatile shooters, with low-light capability, a 16.1-megapixel sensor, continuous autofocus and quick shutter response, so it works in just about any setting.
$699.99 with 14-42 lens
Also consider: Canon EOS M w/ EF-M 22mm F2 & 90EX, $829.99