OP said "tight budget". $400 or $500 for a P&S camera is not what you spend when you're on a tight budget. And if your budget
can stretch up into the $400 arena, I'd actually say go for the Canon S90. The G11 is terrific, but bulky and you probably won't be needing the external flash hotshoe.
I'd say if you're looking at $90 cameras as possibilities, stay out of the SLR arena: the costs are quite a bit higher, and for social picture taking, SLRs can be a serious hassle as it's a lot of gear to carry around, and the bigger the camera is, the more intimidated people tend to get around it. Smaller P&S cameras tend to be the way to go in that kind of situation, unless you're continually taking photos in low light.
The only other camera I can think of that might be close to what you want is the Fujifilm f200EXR. (~$300). It does intelligent pixel binning, and has
a fairly usable iso 800, if you're willing to go with a lower resolution file.