Thanks for the suggestions. Both of the Lion installs are/were CLEAN installs and not upgrades. I will admit that I had not run Onyx until today on my MacBook Pro, but I had used Disk Utility for regular maintenance on my iMac and MacBook Pro. Please don't take my post as a dislike for Lion. I do like it and will continue to use on my MBP. I just can't use it on my iMacs until Apple repairs the crashing issue. I did a google search a few days ago and it appears that many were having similar issues with the iMacs that had Lion installed.
On my iMac I did try to uninstall the extra ram and tried different pairs (at a suggestion from this forum), but the crashing issue did persist. It seemed to happen more on YouTube than with other applications, but the crashing was not limited to YouTube. The iMac runs flawlessly with SL installed.
It will be nice to get Lion back on my iMac since it looked great and I liked the graphical interface a lot.
I never tried it on my second iMac since I did not want to have crashing issues and my wife uses my other iMac, so would not be happy if it crashed during her online classes she takes.
Thanks and I'm open for suggestions. I'm on the road for a couple of weeks, so I only have my MBP until I get back home.