...that has nice graphics.
You're probably going to have to define "nice graphics", because once you get out of the ASCII department, there's a broad variety between graphical styles. If you want to look around for differences, I'd start by checking out the following:
Dungeons of Dredmore
POWDER
DoomRL
ToME 4
IVAN (Iter Vehemens ad Necem)
They're all pretty different from each other, and (IMO) make good use of their graphics.
A few of the classics have tilesets, too. NetHack and Angband, in particular, have official tilesets used, and it's quite possible to download (or create) others depending on your tastes.