Good VNs eh? Guess I'll just listed some of it then.
*in alphabetical order*
Bible Black
Captive Market (It's lilith, so don't play it if you can't handle it.)
Chaos;Head
Clannad (A very VERY great VN of all time.)
Cross+Channel
Daibanchou - Big Bang Age (It has RPG)
Deardrops (Riho route is the best.)
Edelweiss
Ef - a fairy tale of the two
Fate Stay Night
Hanachirasu
Kana - Little Sister
Kanon
Kara no Shoujo
Katahane
Katawa Shoujo (You should have heard of this VN before.)
Kikokugai - The Cyber Slayer
Kira Kira
Koihime Musou (Seriously, I don't want to put this VN here. *sigh* But if you do play it, you can just play Ren, Sei, and Karin route. The rest is mediocre.)
Little Busters!
Monster Girl Quest
Muv-Luv
Muv-Luv Alternative
My Girlfriend is the President
Narcissu
Period
Phantom of Inferno
Planetarian
Quartett!
Saya no Uta
Sekien no Inganock
Sengoku Rance (One of the best RPG VN! At least I think so. ^^)
Shikkoku no Sharnoth
Steins;Gate
Utawarerumono
Wanko to Kurasou
Yume Miru Kusuri
Now you can just choose which one you want to play.
(This list was entirely based on my personal opinion. If someone disagree, well too bad then.)