Weirdly, Mangini in DT made me appreciate Portnoy more. He's still doing lots of cool things, but it's just a bit on the mechanical side for me. I actually really like his work on Elements of Persuasion in particular though, and he does still make my honorable mentions list. His guest appearance on Annihilator's "Weapon X" is also a must hear (watch, actually, for a fun studio clip from the session).
Obviously being a #1 voter of Carey I'm continually impressed with him. I actually view him as a combination and continuation of two drummers I suspect are still to come on the list. So many cool and unique parts, the solos on songs like "46 & 2" and "The Grudge", his incorporation of pads and percussion, he's the ultimate drummer for me. His work in Volto! is also quite different and really underappreciated, a bit more on the jazz/fusion side of things. My favorite two moments of his though have to be either that tom intro to "Ticks & Leeches", or the part at 6:35 in "Eulogy". The latter was one of my favorite achievements of a part to learn to play. It's a relatively simple concept, but the way the hat pattern syncs differently each cycle was maddening to get down. Additionally, it's a joy to watch John Kew's covers of his parts on Youtube, which are fairly faithful to the originals.