David Lee Roth is still the poster boy for worst ever career moves back in the mid-80's by leaving Van Halen - Roger Waters comes in a close second place leaving Pink Floyd at about the same time in the mid-80s .. both had egos larger than any stadium they ever played ..

About the oldest one I can recall hearing a few times is 'Fire' by Jimi Hendrix Experience - other great ones from AC / DC are the first 2 tracks from 'Back in Black' - 'Hells Bells' and 'Shoot to Thrill' ..

Hagar is the better singer - but Roth is by far the better frontman - VH from 1978 to 1984 was one of the best live acts on the planet - EVH was clearly the talent - but as a band of musicians they could not hold a candle to a band like Rush - but DLR - despite the obvious limits of his vocals - was the best frontman / MC ever to take the stage - he kept huge crowds engaged with his manic stage presence ..

The re-fitted design introduced in the first Star Trek film released in 1979 - which was destroyed in the 3rd film "The Search for Spock" - then replaced by the nearly identical "NCC - 1701-A" at the end of the 4th film - is still my favorite design of them all - but man that first film was a real snooze-fest - the ship looked great - the uniforms looked terrible - and the plot was worse than any of the original 79 episodes that ran in the 60's ( and there were a few stinkers among those ) - good thing they came back strong on the 2nd film - or there might never have been a franchise to keep going ..

Syd Barrett to David Gilmour in Pink Floyd should be on this list - esp. when you consider that they started with great promise under Barrett - but after Gilmour ed they became more commercially successful than any of the other bands listed here ..

Peter Gabriel to Phil Collins seems like a glaring omission - but the situation in Genesis was different from most - both were already in the band at the time - and Gabriel willingly chose to leave the group to pursue a solo career - making it necessary for them to replace Gabriel if they wanted to keep going. Genesis took a turn towards much more commercial pop-rock with Collins on lead vocals - and it's interesting how Gabriel mostly maintained his less commercial approach for his first 4 solo records - but his 5th one .. "So" - released in 1986 - was a massive worldwide commercial success - making PG a global superstar almost overnight - and arguably making his solo career bigger than both Genesis or Collin's own successful solo career ..