G1 - Wheelie
Headmasters - Daniel (even in Japanese he sounds annoying)
RID Megatron - not a bad job, just highly forgetable next the Kaye and Welker, I've been trying to remember what he even sounds like and just can't
Armada - Carlos, Billy or Fred (whichever of the two the fat kid was)
Energon - Ironhide's fan club, it was like listening to Wheelie in 3 part stereo
Cybertron - Mudflap (awful French accent) and some of Giant Planet TFs (aka the Scottish planet)

Any Star TV dub

 

Huh. I guess I'm one of the only huys who actually liked Season 3 Megatron's voice. I felt it was perfect for nutjob Galvatron, especially when I watch episodes like Webworld, and I can't think of any other voices that could deliver Galvatron's lines in that episode better than Welker's version.

I was going to nominate that, but no, too easy. Besides, the dub is so bad, it's hilarious.

 

G1 Galvy sounds fine to me too, properly insane. G1 Galvy and Megs are the same character so Welker doing both is a no-brainer to me. Nimoy did a good job but he still reminds me too much of Spock. Actually, Burton's TFA Megs reminds me of Nimoy's Galvy a bit.

 

Can't stand Wheelie. Thats for show.