I'm a melody slut. I dig stuff like In Flames and Children of Bodom, but Nile and Necrophagist do nothing for me. The riffs are extremely technical, but the tone is so muddy and the mixing so deep that it's impossible to fully appreciate (i.e. HEAR) the notes going by. One can get a general sense of what is going on, but detailed listening is impossible for the first time through.
Most of my metal/rockish listening lies along the 80s lines. I fell in love with Uli Jon Roth, Yngwie Malmsteen and Paul Gilbert a few years ago, and haven't really looked back. The playing is fantastic, and the writing is just phenomenal. The harmonies on Malmsteen's Rising Force just seem right to me, and the way Gilbert flies through his solos with such control is amazing.
I'm also in love with Dream Theater, Megadeth, Randy/Jake-era Ozzy, Iron Maiden, some Priest, Steve Vai, and Queen. The prog-metal DT stuff blew me away when I first heard it, and I've gone on to amass every record of theirs (including live albums and DVDs) since Scenes From a Memory in 1999. I'm now working my way backwards. The Megadeth shit I love because it's brutally heavy, very melodic, and has a great feel to it. It's the metalhead's metal. Ozzy and Maiden are self-explanatory, and the other stuff is just what I groove on.
I also listen to random thrash like Anthrax (early-mid 80s only), Slayer, Testament, Exodus, yada yada. But lately I've been dipping heavily into progressive and jazz.