Galaxy S MTP detection issue resolved!
got it working finally after toying with the application and the phone itself..
honestly, i did all the suggestions here including BuddyLee's suggestion but nothing worked including all my research from other forums.. what a waste of my time.
anyways, I finally got it working by doing "Format" for the internal memory.. unmount then format.. and yes, reset to "Factory Default".
after the phone restarted, I connected it to my Windows 7 Ultimate x64bit computer and success.. device manager finally shows GT-I9000, Kies shows it as GT-I9000 and My Computer as well.
Hope this helps anyone out there with the same issue where countless uninstall/reinstall, device manager troubleshooting, Kies Driver Recovery and Reset Phone to Factory Defaults didn't work at all.