If its so good, why do you want to upgrade
Stringreen, you know better than to ask that question - this is Audiogon, after all. :-)
Bbopman, if you decide to sell and replace the AR, you'll get many different recommendations. I've had suspended tables in the past, but now that I have solid floors I prefer unsuspended designs. Right now it's a Technics SP-15 with a Rega RB-250, but my Well Tempered Record Player was pretty good too, if you like to futz. It's more a matter of taste than any inherent advantage.
If you decide to upgrade, go here:
http://www.vinylnirvana.com
and you can see all the options for upgrading. I've corresponded with Dave and he's very knowledgeable about AR and vintage TTs in general. He'll be able to lay everything out for you.
Good luck! You're already starting in a pretty good place.
David