Angel's series finale... I can handle cliffhanger endings when a new season starts in a handful of months, but when it's over? Well, the comic book thing started, I guess...
I don't think they intended that to be the season finale. From what I remember, the cancellation order came after they had already filmed it or something along those lines so they intended to use it as an introduction into the comic book "series", which starts almost exactly where the finale left off. I actually enjoyed it.

The Wire's series finale was perhaps one of the best I have ever seen. It wrapped up everything appropriately for each character and continued the trend that the rest of the series carried on throughout the five seasons it aired. Overall, The Wire was an amazing show.

As much as I enjoyed the last season of Veronica Mars, it was fairly lackluster compared to the first two seasons. The series finale was a letdown in that it ended the show but also because it was not as strong as the other episodes.

Buffy the Vampire Slayer had a decent series finale, far better than Angel's, which is neat because Angel was the stronger show in my opinion.