You know, I use to love really hard stuff like Dimmu Borgir, but now I almost can't stand it. I can't really explain the change, it just grinds on me. I much prefer acoustic or a very clean, stylistic electric guitar piece. Power chords and fast drums just don't do it for me anymore.
That being said, I still like a lot of Opeth, and I find the Blind Guardian and Rhapsody are still listenable, mainly because I like Blind Guardian's choral style vocals, and I like Rhapsody for the vocals, but also for their incorporation of orchestral instruments. I don't like all their songs though, just the ones that have those elements.
To illustrate my point, here are a couple of videos that I find very enjoyable:
Opeth - Harvest
Opeth - Windowpane
SymphonyX - Accolade II
The Tea Party - The Bazaar
The Tea Party - Angels
Brad Sucks - Fixing My Brain
Regina Spektor - Us
Ok, so that last one was piano rock, not guitar. And a female singer. But Regina Spektor is freaking awesome, so it's all okay.
Marsz, marsz, Dąbrowski,
Z ziemi włoskiej do Polski,
Za twoim przewodem
Złączym się z narodem.