There are amazing photographers that produced significant bodies of high impact work with basic cameras (links to photographers not cameras) such as manual focus rangefinder often with a single lens, or a cheap SLR like the Nikon FM-10 with a cheap zoom lens, or even a consumer grade digcam like the Olympus 4040. Most of us aren't at this level though... so we need image quality and whatever help the equipment will provide for compelling images.
IF my primary goal was going after in high quality images in all environments I would pay the weight and bulk tax and bring a semi-pro, or pro DSLR with high quality glass (typically a mix of primes and f2.8 or f4 high end zooms), and likely have two bodies so I wouldn't have to swap lens at a critical moment and at least two flash guns which support wireless triggering.
IF I would looking to a camera that was first "compact" and second provided decent versatility and acceptable image quality in most situations I would pick the new Panasonic GF1 along with the optional digital viewfinder. [I have been using the slightly larger Panasonic G1 for the last year]. The GF1 is not pocketable, but pretty close. Good image quality to ISO 400, usable to 1600 for decent size prints with post processing. Interchangable lens (which are way smaller and lighter traditional SLR mounts). But it can't do "everything". No fast enough for active sports. Not sensitive enough for low level available light photography, and a very so/so flash system which would be a handicap in some situations. The G1 is the camera I most frquently use because it's not a pain to carry. That said, when I really care about the images, and especially when I don't get second chances like shooting the live part of the wedding I wouldn't use the G1. I would pull out a large sensor DSLR.
IF I was looking for a camera that could go into my coat pocket and give me the the best image quality (with a fixed lens) Leica X1; Sigma DP-1*, DP-2. Goes in the coat pocket with a zoom lens (at the cost of image quality) Panasonic LX3, Canon G10, 11 or S90. The LX3 is my daily carry and typically my backpacking camera. I have gotten pleasing images with this camera but there are lots of situations (especially lower light) when it's not that great.
There are lots of camera review sites. Off the top of my head I would recommend looking at dpreview.com, observations from luminous-landscape.com, http://www.reidreviews.com/, and news stories from http://www.seriouscompacts.com/