I love this name too! I do prefer it spelt with two "n"s. It's the original Irish spelling, after all. The first person I think of is
Eamon de Valera (pretty obviously). I think
Eamonn sounds really cool and youthful, but still quite traditional. No bad associations that I can think of. I actually plan on using this name someday.
And what the hell is a "Rasta greeting"? Nobody over here would ever get that comment.