The most interesting cameras of the year so far are the ones that offer ever more flexibility for my nature photography, including lots of small and/or distant subjects (loosely, macro and telephoto) while not wanting to carry more weight than necessary. Lately, the best new options have been the Nikon V1 and the Panasonic GX1, but tue latter possibly needing the accessory EVF: I am stil deciding if I could do with only the rear LCD.
Now Olympus has a temptation in the OM-D E-M5: the first mirror-less offering combining the high resolution (I mean lines per mm, not MP) of an up-to-date 16MP 4/3" format sensor, in-body image stabilization for my legacy lenses ((and supposedly far better than any previous IBIS), and a good EVF, in a body a bit smaller and laughter than the GH2, and far more so that the Pentax K-01. The retro styling has no great appeal to me, but does not get in the way too much. Yest again, great claims are made for AF speed, but I await real testing. I also await the promised 60/2.8 macro, since Olympus has a great history with macro lenses.
P.S. some have criticized the long jumble of a name, but at least it contains not a single X or G or 1.
P.P.S. I am skeptical about the ISO 25,600 claim, but very rarely need to go over 800 when IS is available, so that I'd off my radar.