From where Im sitting, I think these look fantastic. The second version of #3 is much better since you corrected the color. I like the crop and I dont think the expression is all that bad. Mike's vignette example is good. However, you can do it to varying degrees of darkness on the edges and corners.
For vignetting, this is my method if you want to use it (in photoshop).
For full res images, I add a blank new layer, and draw an oval marquee around the whole inside of the frame. Use a feather setting of 200 px so that you have a nice gradient transition from dark to light. Then do Select > Inverse. Select the paint bucket tool and set the opacity to about 30 or 40% depending on how dark you want to make the vignette. Then click on the outer edge. Flatten the layers and save the image. Prepare it for web viewing however you usually do it.
If you have it already in the size for web viewing and want to add a vignette, instead of doing 200 px feathered oval, use 50 px feather (or thereabouts). This also works for different color vignettes, such as white, although I wouldnt recommend using any other colors, since I havent seen it done that way in which it looks any good.
Experiment and have fun. I think the vignetting used in certain images could really give it that last little bit of sophistication and professional classiness. Your work is outstanding.
NJ