I use the suspension.
Here is my system:
Coolermaster Cosmo S case
Corsair 430W
Gigabyte P35-DS3L
Intel E5200 @ 3.5Ghz
Gigabyte HD4850 1GB with fanless heatsink
4 x 120mm fans - using speed controls to make them inaudible
750GB Seagate 7200.10
500GB Seagate 7200.12
The Cosmo S case is actually pretty quiet if you tweak the 120mm fans.
Everything I buy, I buy with noise being a major concern and my system is incredibly quiet and even the seek noise is just barely there. If I did not have red CFLs and a LDC panel, you would have a hard time knowing it was on.
The single best mod I did on my system was to suspend the HDDs. The difference was actually shocking.
I took all the stupid push-button latches off the sides of the 5.25" bays and used some elastic cords from the Wal-Mart sewing section to suspend the drives.
Of course, noise is not an issue for an SSD, but the suspension makes it really easy to put drive in and take them out. No screws.