hmmm... my own top 10 list (currently), in no particular order:
-Ghost Hunt (series)
-GTO (series)
-Boogiepop Phantom (series)
-Record of Lodoss War (OVA series, TV series, and Legend of Crystania movie)
-Cowboy Bebop (series)
-Lupin III (tv series and movies)
-Orguss (original series)
-Bubblegum Crisis (everything including Crash,Crisis, AD Police files OVA's and series, Parasite Dolls, etc.)
-Ikkitoussen (all, but 1st series was, IMO, the best)
-Kino's Journey (series and movie)
Why Kino's Journey???? Well, talking motorcycle aside, I found the themes of each town visited to be quite philosophical, with topics that have been debated many times, yet given a fresh view through a different perspective thanks to storytelling and animation. The actual artwork in many scenes was, while not breathtakingly awesome or spectacular 3-D, rather beautiful like a painting, or subtle. There are other series that I like, and though my top-10 tastes change off and on, I think Kino's Journey will stay up there for quite some time.