I don't know what you really mean by "easily encountered", but the artists I would probably have never listened without AM that I now love are:

The Velvet Underground
Nirvana
Radiohead
Stevie Wonder
Talking Heads
The Smiths
Miles Davis

And that's just in the top 40

I just realized that I never answered this question myself!

Just off the top of my head:

Lou Reed/Velvet Underground/Nico
Franz Ferdinand
Can
Echo and the Bunnymen
Patti Smith
Tubeway Army/Gary Numan
Sparks

moonbeam, yes you have. second post lol.

Oh shit!