Tell us what your going to do with this computer or what to want to put inside.
It's going to be my first build, and it will likely not contain anything larger than an ATX board in the short term, with an i7 and large heatsink. The reason I want a large case is so that I have options for water cooling, 5.25' drives and 3.5' drives. Also, I don't really want my case to be confined inside.
The Corsair Obsidian is not a great case for air cooling but is great if you use water cooling. To me the best full towers for air are the Antec 1200 and Coolermaster Haf 932. Both offer amazing cooling along with plenty of room and good cable management. The Antec 1200 has specific ports for water cooling as well......I can not remember if the Haf does as well or not.
If you find the obsidian expensive then same would be the case with lian-li.. They are costly.. The cooler master ATCS is too plain but very roomy.. Though again, the air cooling is not great.. You should look at mid towers for the best air cooling setup.. If for some reason you need a full tower only, then your best bet would be the cooler master HAF-X..
The HAF-X is a little better looking compared to the previous HAF models but it no way comes even near to the lian-li appeal.. And the PC-A70 is roomy enough (see it in person).. The only thing HAF-X has better is the number of PCI expansion slots and may be black interior coating.. Cooling wise the lian-li will be equally good and more silent..