Strangely, Wembley (7 times to the old and 10 to the new) and Arsenal are the only ones that I have been to both old and new stadiums.
I didnt include ones that I have been to that are no more, or below the stated division include Kettering, Rushden, Bangor City, Runcorn, Northwich, Borough United, South Park (until next season), Glossop.
Then to confuse Gazelle rules more, there are ground-shares including Wimbledon (Plough Lane and Kingstonian), Bradford PA (Valley Parade), Gloucester (Cheltenham), Epsom & Ewell (Merstham). I havent included grounds that I have been to but not for a match or didnt get in such as Wrexham, Wolves, Norwich and Hastings. I may have cheated with Reading as both times were for London Irish Rugby matches. On the other hand, I have been to the Millenium Stadium, Cardiff for a football match (Ireland v Wales ECQ).