I havent dipped into solid state myself, but am under the impression it works just like a normal hard disk.
You should be able to plug them all in, and configure in your bios before you install the OS that the x25 is the first (or second after cd-rom) boot device.
Im currently running a 10k raptor, and two 7200rpm wd blacks in raid.
You cant raid any of yours though, raid requires almost identical hard drives, the only wiggle room is the difference in capacities.