So, here's the deal: every record is rated on its Mix Tape Quotient, or MTQ. This is the number of songs worthy of repeated listenings on that album. For example, a great 3-song 7" would get 3/3 or a hit-and-miss 12-song cd would get 7/12.
An interesting approach, though I'm not sure of how useful it is; some discs worth it for just a handful of brilliant tracks. (One example I could think of could be Slowdive's Pygmalion; as a totality it works splendidly, though there are only 3 or 4 at most tracks I'd choose on their own from it*). And one brilliant track could beat 7 passably good tracks.
And there's the question of what threshold you set for something being on a mix tape; does it have to really stand out, or just be good? Is it bad form to put more than N tracks by one artist on a mix tape (or CD)? (A number of years ago, I was in the habit of putting way too much Paradise Motel on my mix tapes; one or two I made contained about half of Some Deaths Take Forever, interleaved with other stuff. I try to avoid this sort of thing these days, though the last one I made did have several Field Mice-related tracks on it.)
* in case you're wondering, Rutti, Crazy For You, Blue Skied An' Clear and possibly J's Heaven; though the others do a good job of filling out the whole.
Very true, Andrew, I think this system ignores the value that albums DO have as a whole. The only song off Sonic Youth's Daydream Nation I've ever put on a mix tape is Teenage Riot. Does that mean the album gets a 1/13? Hardly; it's the kind of album you have to listen to as a whole - it wasn't designed to be chopped up onto mix tapes as, say, a Ben Folds album might be.
Or indeed Dead Can Dance's _Within the Realm of a Dying Sun_.
And what of albums that are good as a whole but individual songs arn't as interesting... possibly a "DJ set" quotient? How many tracks on there would you mix into a set? And songs that are 45 minutes long (or even just 10), that would be terrible or annoying on a mix tape but are in fact brilliant?
I think a high mix tape quotient would be a good indication of the type of music it is (ie. pop).