There are many threads about which focal length to purchase, but what are factors in deciding how big of a lens to get? Something like this is impressive because it's 77mm http://tinyurl.com/mbftw6 , but what does it do better than something like this http://tinyurl.com/867pku that is 52mm? One of the reasons I bought my D80 with the 18-135 was that I liked the look of the 67mm lens vs the smaller 18-55. I also like looking at media guys do their job with those fat lenses. Have you ever purchased X length lens and then had buyer's remorse because it wasn't large enough?