David Bedella
I'm watching this on BBC America. David Bedella is quite good as Frank. (No, he doesn't equal Tim Curry, but of course that's not really possible.) I had never heard of Bedella, and I was surprised to find that we were born in the same year, both in Illinois. Given this performance, one would never guess that he's 53.
I was in London during the summer of 1979 and saw Peter Blake in the role--also very good.
For me, though, the highlight was seeing Stephen Fry as one of the narrators. (I dearly love that man.)