So, I went and saw Snakes on a Plane (IMDB).
Without a doubt, this was the best movie that could be made about snakes on a plane. That pretty much sums up my review.
Overall, it's one of those films where you can tell that everyone had a blast making it. The plot is mind-bogglingly stupid, but the jokes (essentially, parody of every disaster movie cliche they can pack in) and the main characters make it worth it.
Jackson is great, as you should expect, but several of the other actors (none of whom I recognised) do just as good a job. In particular, the surfer guy murder witness (he's the snakes' target) and the heroic stewardess.
The snakes mainly just give you jump-out frights, although there's a number of gross out shots (guy bitten on the johnson, woman bitten on the eye, icky snake-poison makeup, etc) but these are not excessive. Just very close.
And... well, I was laughing most of the way through. The snakes are just such a stupid idea that pretty much everything that happens is comical.