Don't get me started. You also have to consider what you're going to use the case for while you're looking.
i.e If you want to build a pocket rocket mATX gaming system then you can disregard all the low profile or fixed PSU HTPC cases completely, as they'll most likely be useless.
In terms of gaming, I can throw together a quick list of what's worth looking at.
Silverstone Sugo SG01, SG02, SG03, SG04 (and variants)
Silverstone Temjin TJ08
Lian-Li V300, V350, V351, PC-A03
Antec Mini-P180, NSK1380, NSK3480
Thermaltake Lanbox (and variants)
NZXT Rogue
Coolermaster Elite 341, Elite 342, Centurion 541
If you want a good laugh, search for the Zalman TNN300. It retails at over £400, for a mATX case!