I can't afford to collect but I like the psychedelic art of the '60s
There was the "Big 4" of poster artists in those days. One was Rick Griffin, another was Wes Wilson who designed the poster for the Beatles' last concert: Image: http://www.collectorsweekly.com/articles/wp-content/uploads/2011/09/BeatlesWilson-726x1024.jpg
This was actually fairly conventional compared to some stuff he would later do
I also like the beatnik jazz art of the late '40s and early '50s, though I don't know much about that subject.
I may post some stuff in this thread later