A Fresh Start
If you are starting off with a new, fresh drive then you can skip this step all together. To get a used SSD back to a new state, you need to use software that cleans the drive. There are several pieces of software that do this and the practice has been used for many years. One of the more common is called AS Clean and you can find it here.
To get the best user experience possible, you will want to run Windows 7 for your operating system. Windows 7 is the only Microsoft consumer operating system to support TRIM and in my opinion is a quantum leap ahead of Vista.
A nice feature with Windows 7 is its ability to detect solid state drives when being installed. To make everything nice and easy, build your computer but only install the SSD that is going to run your OS.
Before you break out that OS DVD, go ahead and setup your BIOS. While you're there, set the SATA II ports to AHCI and verify that your SSD is installed on the lowest numbered SATA port. Some motherboards will show it as Port 0 and others will have it as Port 1.
When you install Win 7 it will ask you to create a partition. You are cleared to do so since the OS will automatically align the sectors on the drive, something that needed to be done manually on XP. After your partition has been made, finish with the operating system install but don't load any drivers for the motherboards SATA ports just yet.