As strange as it is. Short Round came to mind. Just can't convince myself as one of the best.

http://hoover.archives.gov/exhibits/...%20HAYEStn.jpg
Hard to top Gabby Hayes for side-kickiness. 191 fim roles according to IMDB, with a huge number as sidekick to the leading man (Roy Rogers, Gene Autry, Randolph Scott, John Wayne, etc...). You young whippersnappers might not remember... ;)

Marty Feldman as Igor in Young Frankenstein.

Tom Arnold in True Lies

Jerome Benton. If the name doesn't say anything to you, think of The Time and the movie Under the Cherry Moon. If that still doesn't say anything to you, then just forget about it. :)

rotfl

from the filename of the .jpg you stole, I'll assume you were posting a picture of Cameron from Ferris Bueller?

Walter Sobchack (Big Lebowski) was the first name that came to mind, but I want to change my answer to agree with Tom Arnold in True Lies. GREAT role!

Short Round? Short Round?! Huh. He's on the top of my WORST sidekicks list.

http://images.usatoday.com/tech/_pho...bacca-main.jpg

http://www.blockbuster.co.uk/bbimage...HenryJones.jpg

http://members.iinet.net.au/~carlm/m...r40_randal.jpg

Of course, the real answers are:

http://images-eu.amazon.com/images/G...ccoy-small.jpg

http://www.startrek.com/imageuploads...he/240x320.jpg

You know which movie I love? "The Invisible Ray." Bela Lugosi was great as Karloff's sidekick.

http://rushmore.shootangle.com/acade...goda_frame.jpg

"You son of a bitch!"

Not for a single role, but rather making a career out of being a sidekick:
Jeremy Piven.

Tuco.
Good the Bad and the Ugly