For myself, I like my PC to be used and not seen or heard. Some people are into ostentatious displays of processing power, though. Those enthusiasts should check out Lian-Li's PC-O12WX. This aluminum-and-glass structure is a uniquely-designed mid-tower case that can put a pair of dual-slot graphics on ostentatious display.
The case has three sections. The main compartment with the main components is divided in two by a steel partition. Motherboards in E-ATX or smaller can mount up to the partition opposite from the usual position, inverted. Then the system's expansion cards go on the other side of the partition, connected by PCIe riser cables. Lian-Li includes a 17" (44 cm) riser cable in the box.
The whole upper portion of the case is enclosed in three tempered glass panels that screw into the aluminum frame with thumbscrews. A small area above the main compartment can take three 120-mm fans, and a frame in the front of the case will accept two more 120-mm or 140-mm fans. Grilles in the leading corners of the case provide fresh air intake for the front fans.
A third compartment in the bottom of the case houses the machine's power supply and storage equipment. Builders can provision a PC-O12WX with up to four 3.5" or 2.5" drives, as well as an additional two 2.5" drives, all in removable drive cages. The case should easily accommodate most ATX power supplies. Lian-Li specifies a maximum PSU length of 9" (or 23 cm).
Your primary concern when picking a power supply will be the length of the unit's cables, though. Since the graphics cards rest parallel to the motherboard, the case can be just 8" (20cm) wide. However, the PC-O12WX is still 20" tall and 22" deep (51 cm x 55 cm). Careful cable routing will be key to making sure everything is connected without wrecking the clean look of the chassis. If this case is exactly the thing you need to impress your friends or attract a mate, it's available now at Newegg for $400.