Originally posted by EricT I agree, there really aren't any advantages to full frame unless you shoot a lot in low light, or print huge sizes (>A3). With the recent introduction of several ultra wide-angles, the crop factor isn't that big of a deal either. In fact, if you shoot birds/wildlife it's an advantage, because you get longer reach at much cheaper prices and lower size/weight.
The main disadvantages of full frame are exactly that, price and size/weight. A Nikon D700 with a 24-70 f/2.8 zoom is quite a beast compared to the K-7 with a 16-50 f/2.8 (or a pancake lens!).
I missed one point I think. Another advantage of FF in low light situation is that it offers larger DOF, contributing better clarity of an indoor scene.
But in the end, I can't justify the expense of getting a FF. Not only camera's more expensive, so are lenses, they are also much bigger. So I guess FF is for professional Studio/indoor low light shoots?
I used to be a Canon shooting, buying those L lenses and was always preparing upgrading to FF when it's reasonably cheap. But then I realize I really don't want to carry those 77mm diameter lens like the 24-70mm f2.8 all day long.