I find it several reoccurring themes in this thread disturbing..
Firstly, the general lack of Opeth's heavy material. I've found that even those who appreciate softer styles of music enjoy Opeth's ability to transcend musical genre and belt out something heavy and soft in succession.
Second, the lack of recognition for My Arms, Your Hearse and Still Life, both of which are phenomenal albums and in my opinion have many more awesome drum moments than Black water Park, Deliverance and Ghost Reveries... Especially when it comes to having a less 'tool-esque' proggy feel. It's alot more rock/metal with latin and jazz influence than prog, drum-wise, which is imo where lopez stands out.
Also, Noone has mentioned that Martin Lopez appeared on Amon Amarth's album Once Sent From A Golden Hall... Which is basically in my opinion not only the band's best album, but it's also my favorite Lopez work. The drumming on that album really shows Lopez's unique styling and his 'metal' side more than Opeth. You can see how different he is from other drummers once he picks up the tempo.
I pretty much agree that Lopez is an amazingly talented and unique drummer, though. He's one of my reasons for picking up the sticks in the first place (after 7 years of bass and 4 of guitar. I'm only 19) and I honestly wouldn't look at music the same way had I not heard his material. He took my perspective away from guitars and towards not only drums but the overall piece of music in its whole.
And to Drum-Head: Axenrot hasn't appeared on any of Opeth's albums yet.. As far as I know when he plays live he pretty much sticks to the script. Axenrot is a great drummer (I love bloodbath) but I don't think we've seen exactly what he's made of..