Lexington, KY. There is no better place to be for any equine medical problem--20 minutes from either Rood & Riddle or Hagyards. We are so spoiled here, best vets & farriers in the world. Emergency staff on call 24/7, will come out ASAP (even to the backwoods of Frankfort at midnight!). Add in other individual practitioners and Woodford Equine... you should be able to find a vet when you need one anywhere in 859/502 area code.
Might not be better, but on equal footing is Ocala, Florida. I am 25 miles from Peterson and Smith, the 3rd largest private equine hospital in the country, with a huge staff of ambulatory vets on 24x7 and 25 miles from the University of Florida vet hospital. And a ton of other vet practice and equine rehab facilities in the area.