As far as LPs go?
They...vary in worth. The MM ones by Oyster are great, for example, if only cause its fun watching him just break down during each of his conditions (or in some cases, the conditions are just plain silly.)
MMX3 was another interesting one due to the "8 different players, all completely different style commentaries!" and what not.
...then there's Super Castlevania which was similar to MMX3 (different players each level), but the commentary was so wasted (like one level started off looking like it'd be good; it was all dramatic with big credits and such, you expect its going to lead somewhere...but it ended up just being "I can't do audio, so here's side comments!" and the comments just sucked. Didn't help the next video was done in the same style -_- )
As far as nonVideo LPs...well, Pokemon Emerald/Crystal are examples of good ones that just kind of poke fun at the game in and of itself, while not actually bashing it (mostly stuff like "Poochyena, the Bite Pokemon! ...and he doesn't know Bite...") or 7th Saga where its just "Its funny cause its true!"
...yeah, LPs worth really depends on if you find a good one or not.