1. Hellsing Ultimate - It'll be very difficult to remove this one from my top spot. Just a great story, great development, great action.
2. Gurren Lagann - I'm actually re-watching this right now, and it's just as good as it was the first time. Break-neck pacing and it actually makes me feel good as a person after some of the episodes, it's borderline inspirational.
3. Berserk - Golden Age was one of my favorite anime arcs of all time, I really wish they'd make more seasons, as I hate reading Manga, but I'd love to know what happens.
4. Trigun - JYB's best role, really good story, love the setting.
5. Hunter X Hunter - Just watched this in its entirety recently. I am mostly over Shounen stories, but this one was so well done. Subverted expectations a lot, and got thought provoking during the Chimera Ant arc.