Like most of you I sat through the final episode hoping for something great and was dissapointed. What really bothered me was the ending and having them jailed for actions that we found enjoyable throughout the years.
However after watching it again with the perspective of it being just another episode I found it enjoyable. Skip the last 5 minutes and it could pass for any other episode out there. As for my botherment about them being jailed - it went away when I realized that their reactions fit perfectly with their characters. They just didn't care that they were going to the bighouse. Most people would be going apeshit about it and these people thought it would be a relief to get a vacation from it all. Even being thrown in with more "hardened criminal" types didn't bother them, well maybe George was a little nervous. Now that's the characters we love and enjoy, at least I do. Although I did think Elaine should have been in the final jailhouse stand-up though.
As for the critics of the ending, what else could they have done? Newhart pulled the dream ending (best of all time IMO.) Countless others have had the final marrage or move endings. St. Elsewhere had the kid's imagination ending. Even a death ending has been used before by Magnum PI (even though it was revised when it was picked up again the next season.) And then you have the life goes on happily endings of just about every other show. No one has done a "everybody goes to prison and likes it" ending before so I give Seinfeld a big pat on the back for that.
Face it, no matter what they would have done people would be bitching about it anyways.