Here's a cool video by Buzz Image, a VFX firm, showing off some of their work on Eternal Sunshine. The video has been online for a couple of years, but Filmmaker IQ featured it on their site a few days ago: (Apparently Buzz is no longer around.)

The hallmark of good CGI is the same as good editing – if it’s done right, you shouldn’t even notice it’s there. Eternal Sunshine of the Spotless Mind had good CGI (Source)

---------------
On an unrelated note, you might've noticed we're doing our annual donation drive thingy, to help cover BCK's running costs. If you feel like helping out, you might want to kick in a couple of bucks via the link in the right-hand sidebar. Every bit's appreciated. :)