~Testament I think has the best overall catalog. All of those other bands were respectable at one time,... but of course there were several good ones that you left out. Kreator and Nuclear Assault, Heathen and Death Angel, Dark Angel and Forbidden... can't wait for the bay area titans tour.
Definitely would have to come down to a battle between Overkill, Exodus, and Testament. Death Angel was pretty cool and of course old Metallica is awesome, but the three above are definitely the best quality thrash.
"I cannot be taken unto, all that I have cannot be taken"
-Chuck Billy-
Dark Angel since they released two albums that were in the top of their respective genres, Darkness Descends for the more normal thrash and Time Does Not Heal for technical thrash.
~Huh? Well I suppose there are such animals being speed and not thrash but I'm not sure what you mean in this case. Killing, Sells and Rust not thrash? Good god man, why not?!
I voted Metallica because that's the band that got me into metal... I haven't listened to them in months though, and I'm starting to get into Slayer.. and Testament is of course awesome.hmmm... i should vote for all of them. hehe
Kreator listen particularly to Pleasure To Kill for example. Perhaps pedantically, I've generally considered Megadeth or Testament to be more emphatically technical. "Thrash" and "speed" are not exactly synonymous, if you ask me.
Testament, of course....no other band has had the technical skill or songwriting finesse of these guys! But I noticed no Euro-thrash was in this poll, i.e. Kreator, Sodom, Destruction, etc...
I voted Testament because I think they have been the most consistent and uncompromising band on the list. Most of the bands on the list have either completely overhauled their sounds (for various reasons) or stagnated (overkill comes to mind, though they still produce some solid stuff). I think Testament has survived the years with their integrity intact, which is more than can be said for a few bands on the list.