ok, pro or no pro photographer, high resolutions are difficult to achieve due to following reasons:
1. Lens sharpnes. Only very high end lenses make a 12mp look good at pixel level. None resolve enough detail for 22 mpx (at least I haven't seen such a photo from a 35mm cam)
2. Depth of field. The aperture in the lens controls 2 things: amount of light going to the lens and depth of field. While the first one is obvious, the second means how much of the picture is "in focus". Try taking a portrait at 3.5f at 22mpix and you'll get only 1/5 of the eyelash sharp and the rest will be "blurry" unless you view a smaller (lower resolution) picture, where the entire face seems sharp.
3. Not really an argument for "less pixels", but the anti-alias filters used on most camera sensors lower the actual resolution of the picture. It depends on the individual sensor, but usually you have only half of the pixel count that is advertised. I.e. take 6 mpix photo, resize it to 3 mpix than resize it back to the original 6 and you won't find any actual difference in detail (except a few resizing artifacts).
Now for the more practical side - I don't care how much megapixels the camera has as long as it's enough (lets say 8) because I don't keep any of them larger than 6 mpix. To my eyes the Canon 5DmkII takes excellent pictures quality wise, especially when resized to those 6 mpix
The D700 from Nikon looks even better.
Anyway, know what would be really cool? Light field photography
now those are the pictures I'd like to have in 100 mpix (assuming the computer can handle it