I'd like to raise my hand on behalf of that other 5% so I can drop in some semi-relevant spam

Most of the banners I churn out are average, because that's all the client wants, but I like finding clients who are happy to think outside the box & try some attention getting ideas - after all, that's the point of banners!!
Latest batch:
http://www.carlajayne.com/clients/vi...e/banners.html
http://www.carlajayne.com/clients/vi...nsbanners.html
RogerV, I get requests for
750/790 x 50
500 x 300 (mailer)
120 x 600 / 60 x 600
120 x 500 / 60 x 500
plus lots of others with 1 side being 60, 100, 120, 150, 180, 200, 134, 240, 250, 300 ......
If you start with the basic templates of 468 x 60 & 120 x 60 then you can just keep changing the size of 1 size to be the above. You end up with a lot of really odd sized banners that are useful because almost all webmasters can work with that range of sizes. Width is more important than height.
Good luck with your banners!