Fringe. It deals with multi-verses and weird things and has wrapped itself up nicely. It lasted for five seasons and I'd say it's pretty well done for what it is.

For books on the semi-long side is Rachel Vincent's -Shifter series. Six books, but they're wrapped up. If you find yourself really jonesing for something and are willing to go with a longer series, I'd suggest The Hollows Series by Kim Harrison. Most of the series I like are either way longer or still ongoing, otherwise I'd offer more.