Well, at $500 you're not really looking for a "P&S" as much as a "fixed-lens" or "bridge" camera.
The Olympus XZ1 is the best spec'd model I know of. An incredible lens at something like 28-105mm f/1.9-2.5. It, apparently, has issues with JPEG processing, but if you shoot RAW it's all good.
The LX5/S100 are the big boys here. Both excellent. I prefer the Panasonic LX5 because of the lens and the form factor. I just didn't care for the "feel" of the Canon. S90-100 were all weird to me.
A dark horse that was pretty much ignored is the Samusng EX1/Tl500. It's been discontinued, but it was/is my favorite of the bunch. Beautiful metal construction, a great, super-fast lens, and incredible noise patterns. Also, you can get like-new copies of it for about $200.
You can't really go wrong in the 300-500 price range. They're all amazing.
PS Sony is about to introduce a new one that has a 1' sensor and a nice Zeiss lens, but it's going to run more like $600-700. I believe it's the "RX1"
The C3 is fantastic, but it isn't a "point and shoot" as such. With the kit lens it's actually quite large and has similar image quality to a mid-level dSLR like the D7000 (they use the same sensor if I'm not mistaken).
You can get a GF3 + 14mm pancake lens for $400, which is a nice combo, but if you want a zoom you're pretty much out of luck with the "serious mirrorless" crowd (Sony, Oly, Panasonic, Pentax, ect)
The Nikon "V series" is probably the closest to what you're looking for. A large-ish sensor, very small lenses, and very good AF. It's been a bit of a flop so far, so the kits have taken a big price tumble in the last month or so. I think you can get a 10-30mm (28-90mm equiv or thereabouts) and a body for $400-500 if you look around.
Again, I think the S100, LX5, EX1 cameras make more sense as they have incredible lenses that would be impossibly large on a big sensor. Also, you can pull very nice 13x19 prints off a clear shot, so resolution isn't lacking.
