I'm not in the market for either Sigma, but I would wait to see whether the DP1 is blessed with the hardware enhancements of the DP2 before choosing. I agree that the WA lens is a big plus for the DP1, especially for landscapes. We've had a DP1 orbiting among the BPL staff and it's a singularly impressive compact camera with no equal in its class.
I've been using an LX3 for a brief time and am very happy with it, but it's not equal to the Sigma in image quality (it's also nearly half the price). Actually, it's better than the Sigma in low light, but not in daylight.
I would probably have gone for a DP1 had the µ4/3 standard not been announced last summer, but am now content to wait for Oly's take on the system, which will likely be out Q3 of this year. I suspect that's the future of lightweight backpacking photography.
So many toys, so few shekels.