Plug for my own LP: http://lparchive.org/Final-Fantasy-IV-The-After-Years/
As for others, if you're into SS LP's, anything by TheDarkId and Orange Fluffy Sheep are good, as is White Dragon's FF9 LP and ddegenha's Bahamut Lagoon, plus a ton of others I've missed off the top of my head. I also heavily recommend Metroixer's Pokemon Blue Let's Break, which completely rips the game's programming apart. If you have a SA account, I'd also recommend Elentor's FF7 LP and ElephantGun's FF6 Let's Break, which shows off some amazing glitches. Oh, and my current FF4 LP, because I haven't plugged myself enough.
I don't really watch video LP's as much, but Pokecapn's LP's are usually pretty entertaining. MeccaPrime's Link's Awakening LP is a thing of beauty I can't recommend enough. And docfuture's Sonic 2: Special Edition is simply something worth experiencing.
There's a s***load more I'm forgetting, but there's a good start there.
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Congrats to SuperNiceDog for winning the Guru for a Super Bad Contest!