It seems to me the ideal camera is one which doesn't involve a series of tradeoffs but instead allows one to dictate the photograph they intend to take.
With current cameras, if you want a shallow depth-of-field (DOF), you need to have your aperture wide open. To have your aperture wide open means more light so you need to adjust your shutter speed to compensate. If you shutter speed is already at its maximum (or faster than you would prefer) then you need to adjust your ISO speed to make your film/sensor less sensitive.
If you are less concerned about DOF but would rather freeze those sprinters in their place, then you need to make sure you shutter speed is set fast enough to avoid any motion blur. Once shutter speed is determined, then comes aperture to compensate, then possibly ISO to compensate even further to make sure you have enough light for your shot. It is all about juggling light.
This whole tradeoff process becomes even more pertinent in low-light situations where there is even less light to be juggled. Regardless of what kind of DOF or shutter speed you desire, you will inevitably need to increase your ISO to get the shot your desire (or use a tripod to keep your camera still for that 0.5s exposure -- or, god forbid, use your flash!). One of the serious downsides of an elevated ISO is a graininess in the resultant photo that, for reasons beyond me, has been mirrored in the migration from film to digital sensors. Is there some scientific reason why both both an ultra-sensitive sheet of chemicals and an ultra-sensitive array of electronic light-sensors need display graininess in roughly the same respect? The most recent digital cameras are finally exhibiting less graininess at higher ISOs, but this is a fairly new development and they are crazy expensive.
Rather than dealing with Aperture, Shutter Speed and ISO I would prefer to have just two big dials on my camera simply labeled depth-of-field and motion-blur. Two dials. That's all I need. Graininess can be added as needed in Photoshop later. Don't make me worry about all the dang tradeoffs, instead just let me craft the photo I want and not worry about having to tweak, test and compensate for the light levels and the sensitivity of the sensor I happen to be holding.
If I want a nice highway-overpass shot of long lines of blurred brake-lights and head-lights all in focus, then crank up the motion-blur and crank-open the DOF. If I instead want a super-crisp capture of that water droplet falling against a soft blurred background, then drop the motion-blur right down to nothing and lower that DOF nice and narrow.
I definitely think we're moving toward this type of camera interaction, but we're still a number of years out. Cameras sensitive enough to even allow this ignorance of trade-offs are out of reach to anyone except high-end digital photographers. Ironic, no?