IMHO, the case is often one of the most overlooked, but ultimately important components of the PC. Although I am myself not particularly interested in case modding, I know there is a growing trend of people who are. And - thankfullly - it appears as if case manufacturers are finally taking his on board and incorporating ideas from amateur case modders in their designs.
It is with these thoughts in mind that I direct you towards a link on Tom's Hardware. This article here, entitled "15 Cases For Review", gives the low down on some of the best choices out there from the major players.