Linux Gazette has a filesystem benchmark article, linked to from slashdot. The results of the benchmark are very interesting...
It's obvious that some filesystems are better for some things than others, and there isn't a huge winner that does good in everything. However, I was really surprised as to how many benchmarks ReiserFSv4 lost. Reiser4 was slowest for removing lots of files and directories, finding lots of files and directories, and creating and copying files. Granted, some of these are Reiser4 losing by half a second, but other times it's losing by almost 15 seconds (copy a 1 gb file). For me this is interesting simply because of the Reiser4 claim that it's the fastest filesystem around. Of course, we all know lies, damn lies, and benchmarks. Of course, I think I trust the benchmarks from LG than from the ReiserFS site :)
Ext2 (the non-journaled FS) kicks everything else's ass a lot for speed, but that's mostly because it's a more simplistic filesystem. For the CPU utilization for the tests JFS looks like it comes out ahead, as it does in the final 'total test time' graph.
Remember the whole 'tools in the toolbox' thing. Course, I'm still not sure what to put as the filesystem for the up-and-coming new ufies.org box... will probably stay with ext3 unless someone has a really good reason to go elsewhere.