Lost captivated for a solid two seasons, then ran down for the rest of its run, but it was fresh (for the time ca. 2004-2010), and still had some knuckle biters from time to time if you were invested in the characters by then.
Evangeline Lilly quite enjoyable eye candy, and the whole Sawyer/Kate/Jack love triangle spiced things up a bit. Some solid performances. Way above average for network fare.
Don't get me wrong, you'll feel let down at the end, but invested and hopeful until then if you don't know the spoilers.