At the risk of sounding like a douche monger, I've always thought disliking movies based purely on the lack of accuracy was kinda fuckin stupid. Whether its historical accuracy, canon accuracy, etc. Cinema as an art medium should be seen exactly as that - art. It's not like they label this shit specifically as a documentary, or you saw it on the history channel. Its entertainment with loose basis in fact.
You're really missing out on some great films if you won't let the directors take their creative liberties, being the artists they are.
Walk the Line totally sucked as a piece of cinematic art though, IMO. Not worth a second watch regardless of accuracy.