The biggest problem turned out to be, of course, how to separate what's "science-fiction" from what's, well, everything else. The easiest approach turned out to be exclusion. The genre doesn't have a precise, agreed-upon definition, as far as I know, but I decided to go with the strictest one that seemed reasonable. Mostly, this meant: no superhero flicks (sorry Mr. Raimi), no fantasy (with apologies to Peter Jackson), and nothing that seemed to lean closer to horror (eliminating the 28 franchise, the likes of The Host and, heartbreakingly, The Mist). That left a list of films that I am comfortable calling "sci-fi."

Unlike some of my cleverer co-bloggers, I decided to go with a more conventional "top 10" for this exercise, though I also offer some bonus categories at the bottom of the post. The digital revolution obviously made the aughts a banner decade for the genre, though the extent to which the big f/x extravaganzas wound up missing from my list surprised even me. I'm glad Jim Cameron got to spend a few hundred million dollars and a half decade developing the fireworks that made Avatar a technological landmark. But -- and this is to take nothing away from Cameron's achievement -- who really needs all that stuff?
1. A.I. Artificial Intelligence (Spielberg) - Not having seen this in a few years, I popped it in the DVD player yesterday morning, worried that the distance -- and the ensuing shifts in experience and taste -- would dull the film's effect. But just like when I first saw Spielberg's stunning masterpiece in 2001, and just like the three or four viewings in between, I was a blubbering mess within ten minutes. A.I. has not aged a day. It remains the decade's most profound meditation on what it means to be human: our evolution, our lives, and our responsibilities in the technological age. In Haley Joel Osment's David, Spielberg found one of the decade's most heartbreaking characters and singular performances. And with the indispensable 20-minute coda, Spielberg posed the decade's toughest challenge to mainstream audiences, who by and large flunked. This is a sci-fi list, but no film from the last ten years means more to me than this one.

2. Primer(Carruth) -- Shane Carruth's 2004 gem has become cinephiles' stock rebuttal to those who extoll the importance of expensive effects: all you need is $7,000, a garage, and a great idea, man. It's a time travel movie that has internalized a key fact: if time travel were possible, we probably wouldn't understand how it worked. The characters here are messing with some deep and disturbing stuff. I don't grok everything that happens in Primer -- few do -- but I sure had a lot of fun trying to figure it out.

3. Donnie Darko (Kelly) -- I almost disqualified Donnie Darko from consideration, because it's a sci-fi movie that doesn't much care about its sci-fi elements -- all of the "Philosophy of Time Travel" stuff is an oblique metaphor for Donnie's yearning to transcend the suffocating phoniness of the real world around him. (This is why the Director's Cut, which emphasized the time travel portals, etc., was inferior to the original version.) But what the hell: I'm not here to enforce some sort of sci-fi earnestness orthodoxy. This is one of the decade's great movies about being a teenager, and we'll let it sneak onto this list, too.

4. Children of Men(Cuaron) - This movie's the whole package: a chilling futuristic vision; a driving, compelling plot; incomparable suspense. On second and third viewings, though, you begin to realize that it's also something else -- an incredible demonstration of directorial virtuosity. Alfonso Cuaron managed to make Children of Men one of the decade's most visually astonishing films (and not just because of the one-take scenes that have rightly attained notoriety), while maintaining its breakneck pace and laser focus. He might be the most impressive raw talent currently working in Hollywood.

5. The Road(Hillcoat) - Coming up with any sort of passable adaptation of Cormac McCarthy's novel would have been an accomplishment. Coming up with one that somehow manages to preserve its uncanny combination of bleakness and optimism richly deserves the awards gold that The Road sadly will not be getting.

6. Moon (Jones) - Reviewing Moon over the summer was a huge challenge, since this is a movie uniquely dependent on the first-time viewer knowing as little as possible about its plot.Since this is a 2009 release that many folks will soon be checking out on DVD (save the date: January 12th), I'll keep the faith with that here. Just watch it. It's brilliant science-fiction that mixes some familiar elements to create something visionary and original on a shoestring (not quite Primer-shoestring, but still comparatively tiny) budget.

7. War of the Worlds (Spielberg)
- If I didn't lose you with my #1 pick, I will probably lose you here. This is Spielberg working in a diametrically opposed mode, using his considerable gifts not to expound on profound questions, but to terrify the bejesus out of you. I know that he rendered the ending hideously implausible by forcing his daddy issues on a story that didn't need them. I know that the aliens turned out to be boring reptilian cliches. The fact remains that the first 60 minutes of War of the Worlds are some of the most intense I've spent in the theater in my adult life. The moment that tripod crawled out from under the asphalt, I was a goner.

8. Sunshine (Boyle) - I had to have at least one space adventure entry, and this is it. Boyle's movie about astronauts sent on a desperate mission to reignite a dying sun is tons of fun in conventional sci-fi ways, but it also breathes unexpected life into the "triumph of the human spirit" cliché. Like The Road, except even more obviously, it has unwavering faith in humanity in the face of apocalyptic adversity. Boyle totally sells that triumphant ending. I'm not seeing Sunshine mentioned in many decade wrap-up pieces, which is a shame.

9. The Prestige (Nolan) - Labeling The Prestige science-fiction is itself somewhat of a spoiler, but what are you gonna do. Christopher Nolan's tricky, startling bit of cinematic sleight-of-hand may end up overshadowed by Memento and The Dark Knight, but it deserves better.

10. The Box(Kelly) - Two appearances by Richard Kelly on this list may be overkill. But I was so unexpectedly delighted by this year's most insanely ambitious film that I couldn't bear to leave it off. Most movies are so earthbound, so provincial, so puny. Here's one that shoots for the stars.

Best Sequels: The Matrix Reloaded (Wachowskis) and The Chronicles of Riddick (Twohy) - Two films that dared to think bigger than their predecessors, with admirable results. Really is a shame about Revolutions though.

Most Underappreciated: Mission to Mars(DePalma)and Dreamcatcher (Kasdan) - I will admit that my uncommon patience with De Palma's visual style and his starry-eyed desire to ape Kubrick may have contributed to my appreciation of Mission to Mars. Dreamcatcher I thought was mistreated -- the tonal shifts and occasional plunges into goofiness seemed like shrewd choices rather than mistakes to me. But I'm probably not going to convince anyone about either of these.

The "A for Effort" Award: Star Trek(Abrams) and Avatar(Cameron) - Star Trek because attempting to reboot this series for a new generation, with a prequel, while not disappointing existing fans, was an immensely difficult assignment that Abrams managed quite admirably. Avatar because -- well, you know why.

Whatever Happened to: Kerry Conran? Seriously, Sky Captain and the World of Tomorrowwas a delightful bit of un-self-conscious silliness -- and a technological precursor to Avatar, to boot. Whatever happened to its director (who was, among other things, one of the brightest and most charming interview subjects I've ever encountered)? Last we heard from him, he was getting kicked off the John Carter of Mars project in favor of Andrew Stanton. Anyone know what he's doing these days?

Speaking of Andrew Stanton: I have to mention Wall-E (Stanton). I couldn't find a place for it on my top 10, so consider it an unofficial #11.

I didn't forget about it, I just didn't like it that much: District 9 (Blomkamp). Sorry fans.