I agree with you on Soundwave + he had like a 7++ cassette-tape posse(bird, cougar, those two rumble bros., bat, rhino, maybe a monkey and something else..) also he made vin diesels voice seem like kim kardashian. My favorite I'd say was Devastator,all the Constructicons. After all the women got done drooling over him they came out with all sorts of 5-man pile up bots, but we all know the Decepticons were maintaining the 'beef-cake status' through and through.
Haha yeah that's Shockwave allright, can't remeber what episode I took that from though. He's probably my favourite Decepticon from the original. Then maybe Soundwave and then possibly Megatron. You have a favourite?