i caught the Ghost, Opeth, Mastodon show a few weeks back when they showed up in CT. it was pretty fantastic.
i missed Ghost unfortunately (the few songs of theirs ive heard didnt really grab me at all, but i wouldve liked to see them).
did make it in time for Opeth though, and they blew me away. similar to Ghost, ive youtubed a few songs and kind of wanted to listen to more, but havent followed up. they were really amazing live (being on mushrooms probably helped a bit). seriously fucking awesome. after their set i almost wanted to go home it was so good. but of course i didnt.
Mastodon was great that night. i had seen them on the tour for the previous album and it was a good show, but nothing special. the venue sucked, there were technical issues and the band didnt seem to be feeling it. i also think that The Hunter is a lot better than their last album, so that helped.
edit: i was informed after the show that the guy who played keys for Opeth was backing up Mastodon during their set. there was also some weird shit going on with Brent doing some high pitched squealy voice harmony stuff, possibly through some sort of device, but i was on the other side of the stage or in the middle in the pit for the show, so i didnt see what was going on clearly over there. some cool shit though.
the venue was also really really good. great space, great sound, and i didnt hear a peep out of security (the way it should be). great fucking show!
and now i think i need to get me some Opeth. no idea where to begin though. My Arms Your Hearse probably.