Depends what you think is sexy and what budget you had in mind, also what size case are you after? Mid tower or full tower? Personally I like the sleek lines of the corsair 650d.
here are a few you could consider,
1:http://www.overclockers.co.uk/showproduct.php?prodid=CA-073-SV&groupid=701&catid=7&subcat=1092
2:http://www.overclockers.co.uk/showproduct.php?prodid=CA-022-NX&groupid=701&catid=7&subcat=35
3:http://www.overclockers.co.uk/showproduct.php?prodid=CA-043-CS&groupid=701&catid=7&subcat=1489
4:http://www.overclockers.co.uk/showproduct.php?prodid=CA-036-CS
5:http://www.overclockers.co.uk/showproduct.php?prodid=CA-008-LN&groupid=701&catid=7&subcat=1447
6:http://www.overclockers.co.uk/showproduct.php?prodid=CA-062-CT&groupid=701&catid=7&subcat=1901
There are others, such as Lian Li`s cases which are at the top of the price gang, though are exceptional quality or perhaps the CoolerMaster Haf-x if you like that kind of look.