It got canceled because it lost momentum. The show was awesome nonetheless, but the first season got caught by the writer's strike and lost momentum. Coming in the S2 ABC didn't really do much for it so it just ended after 13 episodes (and I really doubt the comics are incoming ever).
Also, a Canadian series: Being Erica. Just finished it's 4th (and probably final) season in Canada. I think in the US it's being aired on a soap opera channel but it's anything but that (single camera dramedy) and is a season behind.
If you're a fan of Jud Apatow's comedy, young Seth Rogen, and much smaller/younger/Britishier Charlie Hunnam I recommend Undeclared. It started after Freaks and Geeks was cancelled and lasted just as many episodes, but I really enjoyed it.
Also, like others have mentioned, if you're a Buffy and Angel fan definitely check out Supernatural. I think it's best at the beginning but overall it stays relatively solid to now.