Do you know for sure one 120mm fan will be cool enough?
If not, then the Whisper won't keep it, cool, either. It has a single 120mm exhaust, with no intake options, from what I can see. Those extra fan(s) (1 included) don't do the CPU or video card one bit of good.
Not only is there one less fan and it has less space as it a mid-tower as opposed to the full-tower Whisper.
With the flipped design, and separated compartments, you have room for quite a few drives, but overall, there's not going to be much extra space. A great deal of the space is wasted.
While on that note, however, your video card's length could be an issue for choosing a case. You've got to fit both the card, and any auxilary power connectors.
I'm not necessarily a "Quite nut" as much as I am a "cooling nut," although a quite case would be a bonus.
http://www.bit-tech.net/hardware/cases/2008/11/07/nzxt-whisper-review/4
http://www.techpowerup.com/reviews/NZXT/Whisper/6.html
It just looks like they went, "hey, we should get something like that P180 those kids from California are selling," and stopped when they had something that looked similar.
If you want a larger case, with that kind of 'flipped' design, and drive cages, and sound killing features, the P183 isn't too much more (if buying from Newegg, FI, $15 more).
Some cheaper ones to look at, on top of the Solo, would be Antec's Sonata, and Cooler Master's Centurion 5 (CAC-T05), Gladiator 600, CM 690 II, and HAF 922 (and probably half a dozen more slightly different CM cases superior to their Elite series). Lian-Li's K58 and K60 look nice, too, but I haven't used them.
Might do the destroyer, but that case seems like it's going to sound like a wind-tunnel. Plus there are a few reviews saying the electronics fried or it came beat up. I've not heard much good coming from this community about the cheaper rosewill cases.
Rosewill is largely a rebrander of cheaper stuff, so there's not much consistency--except that most will come in black. One model will be good, yet another one complete crap. The Destroyer could be one of the good ones. As far as sounding like a wind tunnel, that's where a great big ol' heatsink, and a few quiet 120mm fans come in, using the the savings gained from going with such a case.