Heavy bands with (mostly) clean vocals?

Haha I can name a band that I was session drumming for! Uhmm.. you said "no powermetal", and these guys have played power crap fuck shit metal in the past but they're heavier now but still, for whatever it's worth, you might wanna check them out:

Steel Attack (Sweden)
http://profile.myspace.com/index.cfm?fuseaction=user.viewProfile&friendID=63185489

No offence to the guys in the band, but their name is really gay! They're alright people though, really cool guys :)
 
I think Flotsam & Jetsam has put out some great stuff. Annihilator is worth a mention in this category also.
 
Hahaha, I dunno what "fufu" is, but they one of my favorite bands of all time - favorite albums are "One Hour by the Concrete Lake," "Remedy Lane," and "The Perfect Element I," in that order
 
This is proving harder than I thought! Doesn't have to be entirely clean, but the more the better!


Are there minimum requirements for "heaviness" and/or year(s) of operation that we shouldn't bother dipping below, or can we start calling out "Rainbow!" and such?
 
Devin Townsend. Terria has some of the greatest clean vocals & melodies ever recorded. Amazing album.

Another melodically interesting act is VOLA from Denmark. Clean vocals in a Textures/Opeth/Porcupine-esque mix and quite heavy riffs in some places.
Link: http://www.myspace.com/volaband