For years I've used the Fuji Finepix F10 which took really great pictures with 5Mpixels but most importantly was fast enough to take ISO 400 photos. That camera still works really well but is not pretty big. Ideally you want a shirt pocket camera that:
* 8MP sensor and lense quality so you can get A3+
* ISO 400 quality so you can use available light most of the time
* Image stabilizer to future help you get those low light shots
* Aperture and shutter priority to control exposure
* Shirt pocket size
Here are the pro choices as "Luminous Landscape":http://www.luminous-landscape.com/reviews/cameras/shirt-pocket.shtml and "Steve's Digicam":http://www.steves-digicams.com/best_cameras.html reviewed:
* "Sony DSC-W300":http://www.luminous-landscape.com/reviews/cameras/shirt-pocket.shtml. It is a wolf in sheep's clothes. It has a 13.6MP lense and a tiny 1/1.7" sensor but it looks good at ISO4. nice, but kind of big, so defeats the purpose a little bit. You really want something that is shirt pocket size. Most importantly it has an optical viewfinder. However, "Amazon":http://www.amazon.com/review/product/B00153WWRK/ref=cm_cr_dp_all_helpful?_encoding=UTF8&coliid=&showViewpoints=1&colid=&sortBy=bySubmissionDateDescending found picture quality poor. "Steve's Digicam":http://www.steves-digicams.com/2007_reviews/sony_w200_pg5.html as ISO 200 images for earlier W200 (12 vs. 13MP) and was the ultracompact to beat. "Cameras.co.uk":http://www.cameras.co.uk/reviews/sony-dsc-w300.cfm found nothing special about picture quality.
* "Ricoh GX100":http://www.luminous-landscape.com/reviews/cameras/ricoh-gx100.shtml is another no obvious choice, but this one does have a 10MP sensor, 24-72mm equivalent lense. It has a Raw mode but takes 5 seconds to write a single shot! It has a optional electronic viewfinder, so you its easier to aim. Main issue is it is noisy at ISO 400.
* "Sigma DP1":http://www.luminous-landscape.com/reviews/cameras/sigma-dp1.shtml might be a good choice because of its incredible image quality using a dSLR foveon processor. The main issue is that it has slow startup, slow shot to shot and is noisy above ISO 200, so really isn't practical.