Now 10 favorite (reflected in thread title change), even five was too tough (three impossible).
Though, if I had to pick five, I'd take out the Ziggy Stardust double live album and Diamond Dogs, much as I like them, and include the studio Ziggy Stardust (arguably the pinnacle of his career) and Aladdin Sane (which the more I listen to it, find an OVERALL stronger album and superior to DD, which does have great moments).
Top 5 Albums
1) Station To Station (first with the Alomar/Murray/Davis funk rhythm section trio, personal favorite because of the masterful blend of rock and funk, title track his longest studio track [[?]], shows range with one of his greatest soul/funk/rock/pop hits in Golden Years)
2) The Rise And Fall Of Ziggy Stardust And The Spiders From Mars (greatest album?)
3) Hunky Dory (first great album?)
4) Heroes (my favorite of the Eno co-written Berlin Trilogy, arguably his greatest collaboration and, as a whole [[linked larger work nested inside of his total body of work]], one of his greatest and most influential overall achievements)
5) Aladdin Sane (the avant garde piano on the title song OUTro imo one of the greatest in rock history, also stacked with classics such as Jean Genie, Panic In Detroit and maybe his best song, Cracked Actor)
Top 10 Albums (cont.)
6) Low (the first in the critically acclaimed Berlin Trilogy, and neck and neck with Heroes for best, one of the most courageous breaks with his past in a career full of them)
7) Diamond Dogs (break from the Ronson era, the Shaft-like guitar [[skip Pitts influence]] of 1984 prefigures the soul and funk of Young Americans and Station To Station, first self produced album, in addition to lead and dubbed background vocals, most of the lead guitar, synths and even sax)
8) Scary Monsters (revisits the brilliant Fripp collaboration, in his own estimation and self-appraisal, some of his best guitar work, last great album [[?]], 35+ years ago, also the last album with the Alomar/Murray/Davis rhythm section - though Alomar would continue through until Reality in '03, so nearly three decades)
9) Young Americans (even more so than DD, a key transitional album in a career that was almost a continuous series of transitions

, nearly pure soul with his unique funk/rock inflections, Fame one of his greatest and my favorite SONG collaborations, with Lennon - Eno would be for multiple album collaborations, Fripp would rank pretty high up for Heroes and Scary Monsters)
10) The Man Who Sold The World (if not his first great album, his first really good one, tends to be overshadowed in general by a body of work chock full of classic albums, and specifically by his first great work immediately following this, Hunky Dory)
Honorable Mention: David Live (DD/YA), Stage (Low/Heroes) and the Ziggy Stardust Motion Picture Soundtrack (HD/ZS/AS)