Update on my Corsair Obsidian 450D case, with some complaints.......
I've given up trying to silence the case. It's just much too open with its numerous great big fan holes. To reduce noise with this, you need to reduce the amount of noise made in the first place, via quiet fans or fanless devices, and SSDs. It's water-cooling ready (and I'd need water cooling for any more overclocking of my CPU), but I'm not convinced that the water pump would be as quiet or pleasant-sounding as I want, even with a variable-speed model. My current CPU air cooling is practically silent at low load, and I run the machine at low load for 99% of the time.
You need a cable adapter (not supplied) to use the front panel USB 3 ports with USB 2 if you have a USB 2 header but no USB 3 headers on your motherboard or cards. Get an adapter (or PCIe USB 3 card) off eBay, and also a motherboard beeper if you want one, as there's no beeper in the case.
The reset button is ridiculously small and recessed, but you probably won't need it often (unlike me at one point, so I made a remote control - which was ridiculous).
It can't take more than two CD/DVD/BD drives.
The two SSD caddies in the back of the case (behind the motherboard) are neat, but it's shame they're made of plastic rather than aluminium. SSDs can run warm and there's little airflow there. I suppose they don't get hot enough for it to be a big deal, but still it would seem good practice to sink some heat. Alternatively, you can put SSDs in the air-cooled HDD cage (that takes up to three drives).
The quick-release front fan filter panel accidentally pops off too easily while handling the case.
Overall, though, it's a nice case, and exceptionally versatile for the size when it comes to fan options. Still recommended.
See the YACF Classifieds if you'd like to buy the Corsair fans that came with mine. (I'm using only-slightly quieter Noctua fans instead).