I've always enjoyed the way Wayne Harper calls the show at Lincoln. As great as he is behind the mic, he's even better as the emcee at events like the Lincoln Speedway and York County Racing Club banquets (if you get him alone he might even tell you an off color joke or two).
As far as Flo, I love when Chet Christner and Pat Sullivan combine to call a USAC show. Pat is a walking encyclopedia of racing history and Chet's arguably the most colorful announcer out there.
To answer redfred, Dave Hare announces at Baps (Susky).