You've got some good taste.
<honorary like>
Iron Maiden is on my "must see" list. I've seen Guns and Roses er Axl Rose; Sabbath, Judas Priest for their final international tour and I am very lucky I got to see Motorhead. (RIP Lemmy) Maiden is one that Sasquatch is going to use a day of vacation so we can go see them live. I've also loved Halestorm since I saw the Golden God awards and she was first getting started. I'd love to see them as well.
I was a huge Type O Negative fan, and I'm generally a fan of Doom Metal in general. I'm also into industrial, like Wumpscut, old NIN, Skinny Puppy/Ogre solo and KMFDM.
I saw Iron Maiden live with my brother a few years back.
It was a pretty awesome show. During one song, these huge jets of flame came out of each side of the stage, and despite being near the back of a stadium, I could feel the heat a little bit. I felt a little bad for poor drummer Nicko McBrain, who probably got the worst of it.
Anyway, I don't know if I should say this is a confession or just a weird thing about me, but in high school I listened to a lot of extreme metal, including the weird Scandinavian Satanic black metal. I could get away with it because the band logos were almost always unreadable (can you get "Dark Throne" out of this nonsense?), the lyrics were always in Norwegian or Swedish, and even if they were in English, the screams of the vocalists were completely unintelligible. They also all wore corpse paint and generally made themselves out to look like members of the KISS army (check out these badasses), so it was quite hard to be genuinely intimidated by them. Meanwhile, my parents generally maintained a "Don't ask, don't tell" policy on all of this.
I guess I grew out of it, got tired of it, or something, but by the early to mid-2000s I was mostly on to other things. Still, it probably shaped the way I listened to music long after. For example, singing in black metal was not a priority, so I suppose I conditioned myself not to care too much about singing. And to this day, a huge percentage of the music I listen to doesn't have any singing at all.
Anyways, here are a couple samples from my corrupted youth:
Darkthrone - Transilvanian Hunger: The muffled sound of the song isn't due to the sound quality of the video; it was widely believed by black metal musicians that intentionally poor production values made your music more "grim." Also, here an actual lyric: "Hail to the True Intense Vampires!"
Sigh - Bring Back the Dead: Sigh is a postmodern black metal band from Japan. This song is very weird and eclectic, but strangely catchy.
Celtic Frost - "Dethroned Emperor": Celtic Frost is to heavy metal what Joy Division is to Rock and Roll--massive influence everywhere. If you can get past the odd pronunciation of the title ("DA-throned em-PER-or!!"), this song has a nice groove.
Esoteric - "The Secret of the Secret": Esoteric is an extreme doom metal band from the UK; can't think of a way to describe this except to say that it's probably not for everyone. 
Anathema was another doom metal band also from the UK, but they've undergone a very interesting shift in direction over the past few decades. Here's a sample of their stuff from the early 90s, while here's what they're doing now.