No, I'm not back*, just passing through. With some recommendations.
(*Probably)
Mentioned so far:
Naruto is OK if you're watching lots of episodes all at once, otherwise you will get increasingly annoyed with its bad habit of repetition and 'previously on' - anything to reuse past footage (for want of a better term)
Bleach is definitely quite fun - and the filler isn't too bad either, when it's a whole new story arc of filler, though the one-off filler episodes are insta-skips. The manga is definitely worth a read too.
Trigun is also worth a watch - it's the only anime I've ever watched where I've been able to put up with the dubbing rather than subtitling it up, and though it takes a while to get going, it never stops building in awesomeness until the end.
Not mentioned so far (for shame!):
Black Lagoon is entirely awesome: John Woo-esque action and a great set of characters, I'd love there to be more of this made.
Death Note is also fantastic - the only reason I've never seen the last quarter-season of the anime is because I got too impatient and read the manga instead.
I really want to get around to watching an anime called Monster, which looks intriguing, but I have a loooooooooooooong list of 'things I want to watch', so it'll take a while.
Passing mentions:
Helsing (some awesome moments), Darker Than Black (intriguing), Noir (good music!), Devil May Cry (mindless stylized action), Claymore (potential, but I never saw many episodes), Full Metal Alchemist (practically mandatory watching and it looked quite good, but again haven't seen more than a few episodes).
Bizarro mentions:
Elfen Lied is brilliant, but seriously gratuitous - nudity and gore aplenty, which almost put me off.
Serial Experiment: Lain is very very cool, but also very very trippy, and certainly is not for everyone. Also quite hard to describe.
Films:
Anything by Ghibli. End of. Laputa (castle in the sky) and Nautisca (valley of the winds) are my favorites, with Mononoke and Spirited Away coming in close second. Even silly films like My Neighbor Totoro are beautifully made, if not terribly plot-heavy. Ghibli adaptions of Western novels are also fairly good - Howls Moving Castle and Earthsea aren't bad watching, though I don't think any film could do Earthsea proper justice.
Blue Sky (wonderful days) is an excellent Korean (?) anime film set in the future, definitely worth seeing. Other good future-anime would probably include Vexille, Appleseed and the GiTS films.
That's all I can bring to mind for the moment...