It's interesting how so many fantastic authors fall flat when it comes to endings. Like in my experience with Neal Stephenson's books (I've read Snow Crash and Diamond Age), the beginnings and middles are great, but the guy couldn't write good endings.
Huge Neal Stephenson fan here, but I agree... he positively doesn't give a shit about his endings. Everything wraps up in half a page and it's like "NEXT BOOK!" Snow Crash, Zodiac, and Criptonomicon (favorite) all have positively worthless endings. Snow Crash is probably the shortest and worst, though. That said, none of them are BAD per-say, but they're abrupt and obvious. There as-if he's saying, "yeah yeah, you know what's going to happen, so I won't bore you with the details: bad guy dies, THE END". I need to read Diamond Age.
FF8, 9, and 10 all have some of the finest endings in video game history, but all for radically different reasons. 8's FINAL FANAL ending is just dramatic and poignant (not talking bout the weird shit leading up to the ending). I love how it shows the kids being kids in their natural environment, goofing around and celebrating with a camcorder, you don't usually get to see that hardly at all. FF9 is just heart wrenching and beautiful. I'm not crazy about Necron, though, and felt like it undermined Kuja as the ultimate villain (and my favorite in the series), but aside from that it's absolutely flawless. FF10 is just... gut wrenching. Jesus.
Grandia 2 had the worst ending ever (surprised to see this on someones good list). Totally side-steps the major relationship conflict throughout the game in order to not take sides, and turns each character into a milquetoast version of their prior personality. I wanted to scream at the TV. I give this the "Afraid to hurt anyone's feelings" award of the century.
Suikoden V just made me scream. Unless you get all 108 stars (which is almost impossible due to some weird glitches and unexpected permadeaths), he games pulls a BAD ending out of nowhere. Overall, fairly light/medium hearted game that ends with an unnecessary emotional gut punch unless you're ridiculously careful. I even had a guide but still lost 3 stars due to a glitch and a permadeath during one of the under-explained tactical sequences (nothing in the series suggests there will be permadeaths and they are completely random). I ended the game feeling so let down, I had to go online and watch the good ending, and pretend I got that instead, or I couldn't fall asleep that night. Great game, terrible design decision for the ending.