Full frame and so what?

I've been reading a number of posts on photography and camera forums. Some people showed their pictures shot with Canon EOS 5D, a full-frame DSLR, and some people asked for comments for getting 5D and 40D. The reason for 5D is full-frame feature, for 40D is newer technology. Some people shot with 5D and asked questions about vignette in the picture.

I won't want to tell people that I am using a professional tool to shoot a childish pictures if I am not confident. 5D doesn't make pictures look better if the person behind sucks. Here are some examples.
http://www.pantip.com/cafe/camera/topic/O6222586/O6222586.html
http://www.pantip.com/cafe/camera/topic/O6216453/O6216453.html
http://www.pantip.com/cafe/camera/topic/O6210273/O6210273.html