I have a Canon SD870 IS point and shoot and would like to move up a step. REQUIREMENTS: (most important first) Require low shutter lag, very good high-ISO images (say, 5000 ISO), easy aperture priority control for portraits, adjustable-power fill flash, and wide-angle lens (28-90mm equiv). OPTIONAL: Need not have a mirror; electronic viewfinder or live view is fine. Don't need a removable lens. Would like 3" or larger LCD. Want small size, though that's the least important criteria (need not fit in pocket). I'm willing to spend $1500 (incl. lens). Ideas? I've been looking at Canon G10, Olympus E-P1, Sigma DP-1, and Panasonic GH-1, but none seem to quite fit the bill.