I dig Darth Vader alot ... but in much smaller doses. Not only do I not like his entire childhood-to-death story arc, I don't even like him as a stand-alone villain, or as the main bad guy. Perhaps it's because it's so hard to convey a performance with no face ... but I think Vader worked much better as the henchman than as the main baddy. In Star Wars and Jedi, he had great actors to play off - he was subordinate to Peter Cushing and Ian McDiarmid, the badass asskicker to the powerful badguys ... and I think Vader had far greater effect in those cinematic circumstances.
He often seems silly to me in Empire, when he's leading the bad guy show. There's only so much faceless performance I can take. There's likely no better voice than James Earl Jones, but I need a face to convey evil. Playing off Grand Moff Tarkin and Emperor Palpatine, Vader was terrific. Sometimes less is more.
(And yeah, I loved "I am your father." But it all went downhill from there, didn't it?)
.