Some of the procedures in the first post are a little misleading for a newbie like me and can send you running in circles. What I wanted was Stock Froyo with root. I installed Froyo using odin fine, but when I tried to root using z4root, it failed no matter what. So, I moved on to OneClickRootCWM3.zip. It worked fine or so I thought. After spending half a day tweeking Froyo just right, I went to do a backup using clockwork. That was a big mistake since as soon as I rebooted into clockwork 3 it started converting the filesystem to ext4. And stock Froyo won't run on ext4. I was stuck on the boot screen. So, back to odin to reflash stock Froyo.
What I ended up doing was using one.click.root.exploitv2.5.5.zip from the eclair instructions to re-root. Seems to work fine in Froyo, and doesn't automatically convert your filesystem to ext4. Seems like it should be made clearer that you should NEVER use OneClickRootCWM3.zip if you want to use the stock Froyo.