Like Highlander, "There can only be one!" -- Cyril R. Salter's "Wild Rose" shaving cream. I tried the other "major brands", but never found a "scent or slide" that compares with Salter's "Wild Rose". It's similar to Castle Forbes' shaving creams, in that it's very thick -- almost like a soap, but not quite; Salter's not as much as CF, but similar (all of which means that you have to use moderation when loading your brush, but also that that small amount of shaving cream gives copious amounts of lather).

Of course, YMMV.