I first came across LPs from ProtonJonSA, however I've watched all of his LP videos. I've also seen all of chuggaaconroy's LPs so far, but he isn't as amusing as ProtonJon is, but he is a lot more regular and a lot more informative in how he does his LPs.
Other good LPers that I've come across are Slowflake (who has a nice ranting style, but it can get boring), TheKholdOne (who doesn't really stick with any game, but he is hilarious), and PhantomSavage (who has an abrasive but hilarious sense of humor).