Hrant Matevosyan's 'mer vazke' is the best written book I've ever read in any language.
Raffi's "Khent" played a big part in shaping my beliefs towards Armenia and issues of Motherland, shattering many ideas, and strengthening many others.
Baruyr Sevag's poetry has awed me with its intellectual quality.
Yeghishe Charents' "yes im anoosh Hayastani' amazes me, because he so ably simultaneously describes every Hayastantsi's and every Spurkhaye's understanding and love for Armenia. The mutual understanding of that poem alone can define our identity as a nation.
Vahan Tekeyan is a great poet also... waaaay up there in the list of greats.
There are many other authors I love, and many more I still have to read, but as it stands, these 5 take the prize.