After the HD in my old (2006) white MacBook started making funny noises I decided – despite its age, as it is still working fine otherwise – to upgrade it to an SSD. The OCZ Vertex Plus 240GB seemed like a good choice at a reasonable price.
However, while both a Time Machine restore and a new OS X Snow Leopard installation ran fine, the disk was not in a bootable state afterwards. This is where I had to learn that these days you need to apply updates to hardware before being able to use it… Bumping the firmware from 3.02 to 3.55 using the firmware updater found at http://www.ocztechnology.com/ssd_tools/OCZ_Vertex_Plus/ did the trick.
Using Disk Utility, burn the Firmware Updater ISO to a CD/DVD, reboot, hold Option until the boot device selection comes up and apply the firmware update. Reboot, and the disk should be working fine.