I've been bumping into that price also. My "dealer" just dropped their price from $650 to $600. The RX100 now sits in the $650 slot. They've been really patient with me in letting me explore their inventory and supporting me after the sale.
I keep going to the Luminous Landscape and dpreview reviews on the X10 and reading them like the RX100 isn't out yet. They're really quite positive from the user perspective. I find that somewhat amusing because when the X100 came out many users and reviews were scathing about the user interface. Now that the X100 has cooked a bit, the recipe for the X10 seems more acceptable.
I'm using my X100 in a minimalist configuration and I find I rarely have to go to the menu. The buttons offer significant control and now that the RAW button can also be reassigned I think I have a very usable camera. I rarely chimp and I'm confident now that I got the image I wanted. In some ways the resultant configuration is much like a film camera - grab the shot now and review later when the prints get back. I expect I'll set up the X10 in much the same way. Working in this way is making the display info in the VF much less important - however on the X100 everything you could possibly want is just a button push away.
Roger It's still, ISO, aperture and shutter-speed, right?