I used to be into photography in a big way, but I haven't owned an SLR since the film days.
Then I had a Konica, followed by a series of Pentax models. However, looking back I think I'd have been better of with Nikon, Canon, or Olympus for sharpness.
I have, however, been looking at the dSLR market, and am thinking of buying one.I don't think you can go past Nikon for clarity and sharpness so long as you can afford the Nikon lenses too.
Sony don't look like a bad runner up so long as you use the good German lenses. (I think it is Zeiss that fits them.)
In both cases I wouldn't get too carried away with the megapixel count and would put money towards the
genuine lenses rather than compromise that for the extra pixels.
On the other hand I think Canon and Sony get the colour balance nearer right and Canon iS lenses are pretty good.
The new Pentax models are fairly good on colour too but Pentax has always tended to a rather "soft focus" style.
Because I've been travelling a lot I've been using compact ultra-zoom cameras, which are around the $500 mark.I currently carry a Canon SX10iS, which is a 10mpxl job, and has a 20x optical zoom with a stabilised lens.
One of its advantages if you are off the beaten track is that you can run it on 4 of any old AA batteries you can find - that's why I've stuck with it.
(There were a couple of places in India recently where no one could recharge their batteries as there was no power.)
I've looked at the new Nikon P510 with its 42x optical zoom, but it feels a bit flimsy in the handling and its auto-focus "hunts" a bit as you push the zoom.
So I steered a friend who was looking that type of camera toward the Canon SH40iS which has a 36 x optical zoom and better focussing.
The Panasonic models in this type feel really good and controlled to handle, and use (IIRC) Leica lenses, but so far 26x optical is their limit.
I may go for one of those when they bring out one with a longer zoom.
Steve's Digicams still provides sample shots for comparison from various makes and models:
http://www.steves-digicams.com/This site is good too:
http://www.dpreview.com/