There are many Best Of lists. Best RPG, best shooter, best whatever. This list is for players 18 years old and up.
2channelers have picked their favorite erotic games of last year. Here they are (with NSFW embedded links):
1. Sumaga
by Nitro+
Released 26/09/2008
268 pts
by Akabeesoft2
Released 29/05/2008
263 h25 pts
by Akatsuki Works
Released 26/06/2008
212 pts
by Applique Soft
Released 23/10/2008
164 pts
สล็อตby Key
Released 25/07/2008
153 pts
by Alicesoft
Released 29/02/2008
115 pts
by Softhouse Chara
Released 30/05/2008
110 pts
by Palette
Released สล็อต 25/01/2008
105 pts
by Liarsoft
Released 21/11/2008
105 pts
10. FORTUNE ARTERIAL
by August
Released 25/01/2008
92 pts
Eroge Best Of [via Canned Dogs]