Probably was the first banner of Sonic Forever.
This was most likely the second. I wouldn't know which was which. Tres should know.
This was the Sonic Generations banner I posted to celebrate Sonic's 20th anniversary day on June 23rd.
Here's the SF banner which Miles24 made.
Here's the 4th of July banner which Miles24 also made. A definite favorite of mine.
Here's the new and current design for the site banner made by Happyskunk.