TOD:
I had to Google lists of top 70's hits because the 60s, 70s and 80s tend to all run together. It was interesting to see how the very early 70s was mostly dominated by children with The Partridge Family, The Osmonds, and Jackson 5.
Elton John had a lot of great hits in the 70s like "Philadelphia Freedom," "Bennie and the Jets," and "Crocodile Rock." Diana Ross had some of my favorite songs: "Do You Know Where You're Going To" and "Touch Me in the Morning". Then there were one-hit-wonders like Gilbert O'Sullivan with "Alone Again Naturally" - also one of my favorites of that decade.
As previously mentioned by others here, John Denver had several hits, along with Olivia Newton John, and The Carpenters, the Bee-Gees, and Helen Reddy, but they weren't my favorites. I did like Carole King quite a bit.
People who were trying to ditch their past groups had quite a few hits in the 70s: Paul McCartney, George Harrison and Ringo Starr all did well, and Michael Jackson did one of my favorites songs, "Ben" as a solo artist.
There was also some real crap in the 70s like "Billy, Don't Be a Hero" and "Disco Duck."