In thanking you, Mr. SHRC, for suggesting us your Favorite Power Trios I extend the invitation to everyone who wants to contribute to skylyro’s Top 10 Blog to submit their list of favorite artists, albums, songs etc: be it a Top 5, a Top Ten, Top 20 or whatever, I will be glad to publish it!
skylyro proudly presents:
SHRC’s favorite Prog Rock Power Trios
1. Soft Machine
2. Le Orme
3. Emerson, Lake and Palmer
4. Trace
5. Rush
skylyro.com 
Thanks for posting skylyro.
Remains only one band that is not listed in your ranking nor in mine but should be present in all Trios rankings:
THE CREAM!!!