I actually will often make custom vigenettes. I like to be able to decide how quick the falloff is from the center to the edges, sometimes I don't want the center in the center, sometimes I want more than one "bright center". I'll make a new layer, and draw a greyscale gradient in it (usually radial, not always), with whatever offset seems appropriate. More often I'll center it on my subject, rather than the center of the image, depending on the composition. If I want a more complex shape, I'll create another layer in "soft light" mode, and draw another gradient. When I've got the shape I want, I merge all my gradient layers to one, and then run a huge gaussian blur on it (anywhere from 10% to 50% the width of the image). Then I duplicate this layer, put the bottom one in "multiply" and the top one in "soft light" and then mess with the transparencies until it looks right.