I think Tate was at his best in the beginning with the EP thru Operation Mindcrime. The Warning and Rage For Order fall in there as well.
The EP pretty much sounds Maiden inspired, and The Warning has an old school feel as well.
Rage For Order was pretty experimental for it's time, but is a great disc. They kind of had a gothic influence here are there, and used a lot of strange sound samplings. This disc was way ahead of it's time. Neil Kernon produced it, and it's one of his top achievements to this day.
Operation Mindcrime is my favorite from Queensryche ... I take it you already know it well. If not it's a buy or die type disc .. one of the best efforts in metal, and still standing the test of time very well.
Britt
I only have Operation Mindcrime and Empire. Rage For Order sounds interesting coming from a fan, I 'll have to check it out.