4. Megadeth

In April of 2002, Dave Mustaine announced he was disbanding Megadeth after getting diagnosed with radial neuropathy (aka, major nerve damage to his left arm). Following a year of recovery and therapy, Mustaine gained enough strength to start work on a solo album. However, thanks to contract obligations to its European label EMI, Mustaine was forced to release what would become 2004’s The System Has Failed under the Megadeth moniker. Mustaine went on to tour as Megadeth in support of the album with a new lineup (and without longtime bassist David Ellefson). And thanks to the album and tour’s success, Mustaine decided to bring Megadeth out of retirement for good. Megadeth has been going strong since then, constantly touring and releasing new material (with Ellefson back in the group), and even found time to partake in the Big 4 shows.