It also depends on the kernel -- there have been a number of fixes for ext3 over the last year.
Personally, SGI's XFS is my choice. I found JFS to be very slow in production use and reiser just didn't feel like production quality after two crashes where the filesystem was completely trashed. You buy a 380gb Raid-5 set and lose it not due to hardware, but a bug in Reiser, twice. :)
I run XFS on desktop machines and all of the machines at the colo. Its been in the kernel for quite a while and in terms of seat of the pants performance and ability to come up on reboot quickly, it just seems to be the filesystem for me.
We have a few machines running reiser, and if I had the time, I'd convert them. The only benefit I've seen with reiser is that if you have a ton of nested directories, its directory hash method makes it very quick.