I second VA-11 HALL-A. It's kinda like a VN and a game mixed together, so win/win imo. (Also awesome graphics, characters, musics, etc. as already mentioned).
If you're looking for other VNs, Key VNs (Clannad, Planetarian, Little Busters, etc.) usually have good discounts during the summer sale. Himawari's also very nice. I feel like it's the type of VN that would have a little something to appeal to most people.
As for me, I'm thinking of getting the Dangan Ronpa bundle once I get paid next week. Maayyybe Legend of Hereos: Trails in the Sky but not sure yet.