That reminds me, I'd also add Pushing Daisies. Another great show that was tripped up by a strike (I forget if it was writers or actors), and cancelled too soon.
Yes, a fun show, but at least NBC allowed them to make a 2-hour finale to wrap things up after the cancellation announcement. Most series don't get that consideration.
Surface, the NBC sci-fi series from 2005, which ended on a cliffhanger at the end of Season One.
I also think The Golden Girls could have continued for several more seasons if they'd simply kept the same format/setting and cast a new roommate to replace Bea Arthur, rather than changing...