Oh, and just to say something relevant... Cold Sweats, maybe? They certainly have clarity and definition, lovely versatile neck pickup. The bridge pickup may be a little "cold" depending on the type of clean tones you're after.
I generally don't use the bridge for clean tones. I like the smoother sound of the neck when playing clean. The Cold Sweat may be colder than some of the other BKs, but it's still hotter than the Dragon II I have now (rated at 12k).
Bare in mind that HUGE Isis sound is mostly from a neck humbucker (one of the guitarist uses a tele custom with the neck humbucker), so you would be looking for something open and clear in the neck, so not to turn to mush with distortion. I second the Holydiver suggestion. My favorite humbucker so far.
Actually the past two times I've seen them (June 12, 2009 and April 27, 2008) they haven't used teles. They seemed to have switched to a smaller maker that makes guitars with aluminum necks and have reflective bodies. I can't seem to remember the name however...
Anyways Cold Sweats are definitely an option now along with Holy Divers and Nailbombs. I'm leaning towards the Cold Sweats as I generally like to play with lower gain anyways (I usually set the gain knob on my Ecstasy to around 10 or 11 o'clock on the low gain structure). Thanks for all the replies guys; this is a really helpful forum. More suggestions are certainly welcome!
BTW Twinfan: if you aren't a fan of the growled vocals in Opeth I highly recommend checking out their album Damnation. 100% clean vocals and some awesome 70's inspired prog-rock. :headphones5: