I love Silverstone HTPC cases.
I own the
LC-13B-E and am very satisfied with it - you could also look at the bigger
LC-17B.
Avoid the cheap Nmedia cases - they are cheaply built and very frustrating to work with in my experience.
By the way, your Sigmatek cooler will fit in neither case above - and I think you would be hard pressed to find an HTPC case that accommodates tower coolers, like the others said, except for the Scythe Katana3, which fits in the Silverstones by 1mm (currently using it).