Well, their old standby used to be the PC-60/65/7075, but a lot of folks are liking the newer V-series (with the PSU at the bottom, vented for better heat dissipation, and with the standalone drive cage that keeps the heat from those further from the CPU).
example of PC-65 case (they come in silver and black, with and without preinstalled windows)
example of V-series case
The build quality on all their cases I've seen is excellent. They're not cheap, but you get what you pay for... I'm never using a cheap steel case again. I had to lug one of those around a couple weeks ago, and I forgot how much they weigh compared to the aluminum cases.