If I had to list the hills I have climbed most often, Black Hill would definitely come top. ( I've spent a lot of time on Kinder and Bleaklow but rarely bothered with the trig points)
The second most frequented summit is Diamond Hill in Connemara. I'm pretty sure I've done it nine times.
imagine my surprise, even joy, to discover that the summit of Diamond Hill is on exactly the same line of latitude as my house, to the second!