Top ten lists? Hmm.. requires some thought - and don't have time to think on it right now, but I'll post a few
1. Nausicaa - My favorite Ghibli Flick, and my introduction to Ghibli. Close to this are Tonari no Totoro, and Grave of the Fireflies....
2. Gunbuster! Topo wo Nerae - Old school Gainax, never gets old. Not to mention the origin of the "Gainax Bounce"

3. Tenchi Muyo! Ryo Oh Ki OVA 1 Consistent high quality and a benchmark of the Harem Genre....
4. Twelve Kingdoms - I've only watched the first 4 discs but this is high quality fantasy, with no fanservice and a serious story.
5. Nadia: Fushigi no Blue Water - Another Gainax series with an awesome cast and even more awesome ending. Sure it's got filler but it also has a lot of charm.
6. Hajime No Ippo (AKA Fighting Spirit) - consistent comedy, drama, and kickass fights with no resorting to anime dbz style powerups. Has been consistently good for the past 25 episodes, with around 50+ more to go.
7. Rurouni Kenshin Trust/Betrayal and TV series - This series was one of my first truly LONG series I collected as stuff came out, and dammit it is good. A blend of great action, drama, and comedy (yes, it has superdeformed chars. ) with the OVAs that just redefine action and romance....
8. Revolutary Girl Utena - This series is weird, in both terms of its animation and plot. Yet the way the stuff gets resolved towards the end makes for an immensely satisfying conclusion (with some things left in the air)
9. Mobile Suit Gundam Movie Trilogy - Old UC Gundam manages to satisfy my mecha needs, and does it with attention to the human aspect of war and politics (and proves that war is the result of politics failing to produce a peaceful outcome to a conflict.) Amuro Ray and Char Aznable set the stage for the Gundam craze, and the movies are a extremely good condensation of what makes UC Gundam so good: focus on the humans and their issues rather than the mecha....
10. Rahxephon - an extremely interesting blend of action, mecha design, and story. Well plotted and advanced, and not a EVA rip off as some would put it...
Noteables: Bleach/Yakitate! Japan/Samurai 7/Gankutsuo = these are hilarious and fun shows with compelling action, drama and comedy. Try to see them when you can.