drainpipe

I'll assume you don't want metal with harsh vocals.

Porcupine Tree is a good progressive rock band that has been mentioned many times in this forum. They have catchy accessible songs without cliched lyrics. Deadwing is a good starting album. If you like Porcupine Tree, check out Opeth's Damnation album*. Dream Theater's definitely another winner. To put it lightly, you don't have to worry about deficiencies in the lead guitar department with them. Check our their Images and Words album. I assert that Iron Maiden is still relevant enough to be included in this (their DoD and BNW albums were terrific). Everyone loves Iron Maiden. Show me someone who says they do not, and I'll show someone who has not heard "Hallowed Be Thy Name." Kyuss, Fu Manchu, and the rest of the stoner rock genre are also terrific if that's your cup of tea. They have a fairly fuzzy sound, but they're catchy enough.

And just to blow their nu-metal minds, slip in a few In Flames songs from The Jester Race. It's accessible enough to someone used to having a little harshness in music might like it.

*I do NOT want this to be another huge shitfest about Opeth and Damnation not being a good representation. There is no reason to recommend any album but Damnation when you're not talking about death metal. That was the reason I mentioned Damnation in the other thread and not something like BWP or Still Life.

edit: Oh yeah... you're DJing which probably means people will be dancing. Some of the bands won't work because they like to change their tempo a lot which makes for awkward dancing. And yeah, the music most people dance to is crap. It's unavoidable.