I had the good fortune to see Q.I. last week and I have to say that Sandi Toksvig is absolutely awesome. She runs the show (and Alan) just as good as Sir Stephen did.
I would recommend that you should get Rory McGrath, Brian Blessed and Dave Gorman on the show soon.
Thank you for many, many years of good humour and fantabulous knowledge - may it continue for a long, long time.