I'd probably consider the Canon Powershot S90
to be the successor to the A series. It's canon's response to the enthusiast-friendly Panasonic Lumix LX3 and Ricoh GX200. Lots of manual controls (including a front-mounted control ring), a fast wide lens (28mm equiv and f/2 at wide), a 1/1.7in sensor and a 3.8x zoom in a pocketable compact.
If you don't need/want the manual controls, you should consider the IXUS range for portability.
If you want even more manual control, consider the Powershot G11, which is bulkier and heavier (but also a lot tougher).
I'm not even going to bother recommending things like the Sigma DP2, Lumix GF1 etc., since if you wanted them, you'd already know.
The S90 looks great, but it's quite expensive. I was hoping to find a compromise for a bit cheaper.
The Elph/IXUS range is decent, but uses Li-Ion batteries and I'm not sure how the image quality is. My impression is that IQ is a bit soft.
Th G11 competes with the S90, IMO, but it's probably a better deal all around in terms of build quality and IQ. Still too expensive for what I want, unfortunately.
Sigma and Panasonic's offerings that you mentioned are interesting, but fail in one or more categories. What attracted me to the Canon A series originally was that it did some things (manual controls, IQ) excellently, and did everything else at least acceptably.
@ JAE: The A1100 is close, but I'm not sure I'm willing to give up manual controls just yet.
None of the usual suspects have in-depth reviews on any of these cameras that make comparison easy. I am interested in hearing personal impresions of these new cameras, if anyone here owns one of 'em.