I can't help with all of them, but i'll try:
Rise To Remain/Social Distortion
I actually turned up to a Korn concert a couple of months ago, and walked straight back out when i realised that Rise To Remain were the support band, and came back after they'd finished. On the flipside though, i've never sat and listened to Social Distortion, but they'd still by choice of the two.
Monster Magnet/Murderdolls
I've seen Monster Magnet before and have to say, they didn't do a great deal to keep the audience engrossed. It was a festival show, not one of their own, so i guess they were kinda half arsing it. I can't actually remember if i ever saw the Murderdolls before. If i did it would have been waaaaayyyy back when they released 'VotMD', but i DO know i've seen Wednesday 13 before as well as Joey Jordison in many different scenarios, and both gave amazing performances, so the two combined should equal similar results i'd have thought. The 'Dolls get this one.
I can't stand Slash, but if you've seen one Slayer show, you've seen them ALL, literally watch any Slayer set and you've more or less seen every show they've done since Kerry King shaved his head. Unless you love, love, love, LOVE Slayer with a fiery passion, you'll find them to be boring as fuck on stage. I guess i'd pick Slash purely to say I've seen him perform, but i wouldn't expect to enjoy it, but that's just me.
Melvins/One Day As A Lion
I've never heard of either of these bands, sorry.
High On Fire/Bullet For My Valentine
BFMV are good as long as you're not stood too far back and the sound crew don't keep fucking with their levels throughout the set, which is what happened when i saw them last. I wouldn't waste my time even contemplating watching HOF.
Queens Of The Stone Age/Rob Zombie/Coheed and Cambria
Zombie without a seconds hesitation. I'm not massivley into C&C, and while QoTSA are amazing, you'll probably get a better stage show out of Zombie, plus his most recent album is stunning and he'll probably do some White Zombie stuff too, but which ever you choose out of Zombie and QoTSA, make sure to go see the other band do their own tour when you get the chance.
Dimmu Bogir/30 Seconds To Mars/Gang Of Four
Lol, you've picked the Black Metal band over those two? Fair play mate. I'd say only go and see DB if you're a big fan and you know their tunes well. Black metal bands don't tend to do huge stage shows unless they're Immortal or Cradle of Filth. Once the corpse paint and giant spikes are on, that's about as far as they're willing to take it normally. I've never seen DB, but based on seeing Arch Enemy, Satyricon and a few other Black Metal bands, i think you'll get a more energetic show out of the other two bands.
When i saw Satyricon, i was about the only person in my section who knew any of the songs, and everyone kind of just stood motionless and watched them do their thing, with a look of confusion on their faces, so while i fuckin' hate 30STM and never heard of Gang of Four, i'd
still say don't watch DB unless you're a BIG fan of theirs and you've
always wanted to see them.