One of the most welcome trends in photo equipment in the last few years has been the emergence of high-end compacts. That is to say relatively small cameras with sensors with larger individual pixels than most point&shootsm fitted with fast high-quality lenses, convenient controls, better-made bodies, and more refined interfaces. All this can add up to a small camera that is more enjoyable to use and can deliver surprisingly good results. Often even in low light and without flash, something that you would ordinarily want an SLR with a higher-end lens for.
A typical example has a sensor with pixels that are 2x the size of another compact while having a lens that is not only better corrected but also takes in 2x-8x more light (depending on zoom setting). This makes a big difference, especially in low light.
There are even some advantages compared to SLR-type cameras. A typical high-end compact is fitted with a lens that takes in 2x-8x more light compared to kit lenses that come with SLRs. While the individual pixels on SLR sensors are significantly larger (5x the size), the extra light brought in by the lens can be a big help in bridging the gap. While it is certainly possible to get comparable lenses for SLRs, that can add considerable expense and bulk to an SLR system.
All the following cameras employ roughly the same sensor. The differences are primarily in lenses, processing done by the camera, and form factor and design of the body. All are in the $350-500 price range.
The newest and probably current best of breed. The lens is an extremely bright f/1.8-2.5 over the very useful range of 28-112mm. There are two dials for control including one around the lens. And there is a flash hotshoe for an external flash. Bit larger than the Panasonic LX5 and introduced at $100 more than others.
A predecssor of this camera really kicked off this segment in recent years and became something of a cult camera (in both Panasonic and the more elegant Leica body). The lens is a leica-branded very bright f/2-3.3 over 24-90mm. Compared to the Olympus XZ-1, the lens is significantly wider but a bit slower. It's arguable which one is a better lens to have. The 24mm gives you a very tempting and still unusual for a compact perspective and I would prefer having that. On the other hand, if you need all the light you can get, the Olympus is hard to beat. LX5 also features a flash hotshoe and quite a nice control system.
The smallest of the cameras and the only one that can actually fit in the pocket. The lens is a f/2-4.9 over 28-105mm. The zoom range is very useful, but it's only in the 'fast' category in the first half of it. It is also close, but not quite the same quality lens as the two above. But the control system is excellent and it can't be beat in the size.
Ricoh GR-D III -- this series was around before this became a hot market segment. It is a beautiful photographer-focused camera with many thoughtful features and a terrific fixed 28mm f/1.9 lens. There is no zoom, but the image quality can be superb and it's a low-volume camera. It's unusual and you'll look like you know what you are doing if you have one of these.
Samsung TL500 -- 24-72 f/1.8-2.4 lens makes it very attractive, but it's a bit large for me and it needs some refinement before it can be great. Wait for the next version.
Canon G12 and Nikon P7000 -- Also quite popular, but in my opinion they are too bulky for what they are and are fitted with slower lenses. Not for me.