If I were to setup a new computer intended for single user use with /home on a separate partition, what would be the best file system to use for that partition? Would you use ext3, ext4, reiserfs or something else?
Any of the currently available Linux filesystems will get the job done. ext3, ext4, jfs, xfs, reiserfs, they all work and generally work quite well. However you have to define what you mean by "best" before one can be selected, as the different filesystems each excel in different ways.
If you wan't maximum reliability and recovery, ext3 is the winner. It's run on more Linux boxes than any other filesystem, and has better recovery tools than any other filesystem. However, it's the slowest filesystem, too.
If you want better performance, jfs, xfs, and reiserfs can all be an option. In my general experience, they will all outperform ext3 in general, and in certain cases they'll outperform it by a lot (deleting large files being a great example). I've used each of these 3 filesytems with a lot of success in the past, and would have no problem recommending any one of them for /home. Each one has its own quirks and advantages. The biggest disadvantage is that they're not used quite as much as ext3, so there's that rare outside chance of running into a bug (unlikely), and if there is ever any problem, you'll have fewer tools to support recover (but you should be making use of your backup at that point anyway, so that shouldn't be a big deal ;-).
ext4 is kind of the odd man out right now. It performs better than ext3 (ext4 is more on par with jfs, xfs, and reiserfs), with better recover tools than the jfs, xfs, and reiserfs. However it's also the newest and least tested of the bunch. Some people have already run into some oddities and problems with it, so a lot of people are recommending against it for production use for a little while longer, until it's gotten a few more bugs shaken out.
If it were me, I'd probably go with jfs right now, and if I built the same box in six months or so, I'd almost certainly go with ext4.
Personally I would just use ext3. It's tried and true. Ext4 will replace it but there has been issues with lost data.
Ext3, with data=journal. You're unlikely to actually need high I/O performance from your home directory.
When I used ReiserFS, there was a 30 second wait just to mount the partition!
Ext4 may be too early for home use. Certainly interesting, but the performance gains are likely not worth the risk.