Ext2 or Ext4 for bootable USB Flash-drive with Linux?

I want to install Ubuntu to a USB Flash drive (so I have my Desktop everywhere and can customize it as I want).

I'm still choosing what's the best filesystem for the USB; Ext2 with no journaling or Ext4 with journaling but performance increase? I know that journaling will probably reduce the life of the USB flash drive dramatically, so is Ext2 the obvious choice?

Or is it a bad idea to install Linux (Ubuntu probably) on a USB Flash drive? I tried running a live CD from the USB drive, but it wasn't very customizable - which is the point of carrying my OS with me.

I personally have installed Debian (not ubuntu) to a thumb drive before and absolutely loved it. It makes it very convenient and i wouldn't have it any other way.

I personally used ext2 as I was too worried about the writing affects of journaling that would eventually kill my stick.

I can tell you that with ext2, i have been up and running for roughly 9 months almost none stop. I haven't noticed any problems nor real slowdowns due to my usage.

The only recommendation i have is to run fsck everyweek. This should allow you to see the 'bad sectors' of the drive and it will continue to work around them. That being said, i still do not have any bad sectors and it's working like a charm.

I'd highly recommend a thumb drive linux (next i'm going to try fedora instead of debian) for anyone who travels often and doesn't want to be tied down to using what is available where you are.