At the negative end of the spectrum: Battlestar Galactica.

• Must have been a show that was good enough to care about in the first place;
• Not only fails to resolve long-standing plot and character threads in a satisfying manner, but which resolves them in a manner that is stupid, insulting, and throws into question the events which preceded it;
• Heavy use of deus ex machina;
• Has lots of close-ups of Edward James Olmos' face, which resembles not so much a human face as an English muffin with a mustache;
• You, as a viewer, would have no interest in continuing to follow the characters story where they have been left;
• Is booooooooring;

Score: -10

At the positive end of the spectrum, Angel.

• Provides satisfying resolution to long-standing character and plot threads;
• Unexpected twists and turns;
• Leaves you wanting more;
• Has a dragon;
• Pays homage to one of the great movie endings of all time;
• Displays the testicular fortitude of the shows writers

Score: 10

So, where do some finales rank on this scale?

Seinfeld: 2 (one of the all-time funniest shows went out in a mostly laugh-free episode, although our heroes ending up in jail certainly showed testicular fortitude)

Lost: -8 (here's what I said when I named it the #3 show of the aughts: "This feels a little premature. Depending on the final season, this could turn out to be one of the best shows ever made, or a total disappointment. Such is the highwire that this show has walked from its premiere season. But, as with other seasons, I remain wildly optimistic." Stupid Jesse.)

Buffy the Vampire Slayer: -2 (not so much deus ex machina as deus ex Willow)

The Wire: 8 (especially loved the closing "life goes on" montage as McNulty looks out over the city)

The Sopranos: 7 (almost entirely on the strength of the final scene, which, once you can re-watch it without the initial "oh shit did my cable just go out" surprise, is a tiny little masterpiece; also, the Journey song, which is already in your head)

House: 5 (I know it hasn't ended yet, but I'll be so glad when Fox puts this wounded deer out of its misery that it'll be at least a 5 if not higher)