I hope I'm not offending anyone, but quite a few of the sites I've seen have pretty bad and old design. Lots of animated gifs, horrible backgrounds and use of fonts... they look like crap. But the content are usually good. So don't let bad design skills stop you from entering a site.
A few starters (in no particular order):
- The Reel Image: http://www.thereelimage.co.uk/
- British Film Collectors Convention: http://www.bfcc.biz/
- The 8mm Film Format Metadictionary: http://lavender.fortunecity.com/lavender/569/
- The Story of Blackhawk Films: http://www.filmclassic.com/Blackhawkhistory.htm
- Robby's Super 8 Homepage (German only): http://www.super-8-hobby.de/
- Super 8 Wiki: http://super8wiki.com/
Other stuff:
- Paypal (Most dealers use this, including eBay): http://www.paypal.com/
- The Big Cartoon Database: http://www.bcdb.com/
- Internet Movie Database: http://www.imdb.com/
- Paul's 16mm Film Collecting Pages: http://paulivester.com/films/films.htm