What an ace thread.
It's tricky with Collins, as his Genesis work is so intertwined with his solo stuff. But Mama from the s/t album is absolutely awesome, and lots of Invisible Touch is good, esp. Tonight Tonight.
McCartney's solo career is bits and pieces really isn't it, and it doesn't feel particularly substantial. A lot of people really rate McCartney 1, arguing it's a bit of a precurssor of lofi singer-songwriters, a kind of Madcap Laughs type thing. But I'm not particularly arsed about it. McCartney 2 has some rather good disco moments on it I think.