If the question is point-and-shoot vs. SLR, for the last two years I've used a Nikon D80 (SLR) with 300mm f4 lens and 2x teleconverter. But for my first year of bird photography I used a Canon S2IS and a Panasonic FZ30 (both with teleconverters).
A few comparisons.
The point and shoot outfits cost less than $500, the SLR outfit, closer to $5000.
The point and shoot equipment (particularly the Panasonic) is MUCH easier to use. When I began, with no photographic experience, I would not have had a clue how to use the Nikon.
The point and shoot cameras are light and easy to carry around all day hiking. I can't hold my much heavier SLR camera and lens steady without a tripod.
If you get nice and close, the point-and-shoot cameras can take very nice photos. For comparison, any of the photos in my gallery before about July 06 are point-and-shoot, and after that date are SLR. The last five photos posted to my gallery http://www.whatbird.com/forums/photos/nieblas_gallery/default.aspx (on the right see the "recently added" column), were all taken with point and shoot and are still some of my favorites.
In part because of pixel density, in part because of the finer lens, and in part because of the way SLR cameras work, the SLR setup gives a much smoother image, capable (as photogog pointed out) of being blown up much more, without breaking down and turning grainy. Also it becomes possible to better correct for many of my photographic shortcomings after the fact, using photoshop. That's why, in spite of all the good points of point-and-shoot, I'm very happy with SLR now. But, for me, when I started, it would have been a mistake to lay out that kind of money right away for a camera I wouldn't have been able to handle.
Chris from Denver
