Got a trip coming up and it seems like a good chance to test the Olympus OM-D MD-5 (before the MD-1 comes out 🙂
The next question is what lenses to try. DXOMark has a list of lenses it likes as does Cameralabs, so here are some conclusions:

• Panasonic Lumix G 7-14mm F/4. A little slower than F/2.8, but with the low light performance of the Olympus, shouldn't be much of a problem. Super wide at 14-28mm effective. It has a DxOMark score of 15 with a 10MP effective (on a 16MP sensor, not bad).
• Panasonic Lumix G X 12-35mm F2.8. This is the familiar 24-70mm range that is a traditional standard. It gets a DxoMark of 19, although sharpness is still 10MP.
• Panasonic Lumix G X Vario 35-100 f2.8 has a DxoMark of 18 and 10MP effective.

For prime lenses, the quality is of course higher, so the

• Panasonic Leica Summilux DG 25 F1.4 gets a DxOMark of 23 with 11MP sharpness.
• Olympus M.zuiko Digital ED 75mm f1.8 get a DxoMark of 27 with an amazing 13MP sharpness for a 16MP sensor!

Lensrentals.com makes this reasonable with a $600 dollars for two weeks to try nearly$5K worth of equipment!