Just got an OCZ Vertex2 (120gb) and installed windows under AHCI (install and configuration/optimization of drive went perfectly)...
However after installing windows I plugged my HDDs back in and, and can no longer boot in to windows on the SSD unless the drives are unplugged... Do I need to reinstall windows with all the drives plugged in or am I totally missing some configuration in BIOS?
The very first thing that popped into my head is that a boot drive is specified in BIOS. When you start your pc go into BIOS and check which drive is designated as the boot drive. Set it to the correct drive.
Normally by default the boot drive should be plugged into the SATA0 port rather than the SATA1 or SATA2, etc. etc. ports.
Is your other hard drives formatted? If so, you might try booting without the hard drives plugged in, boot up than connect the hard drives & allow them to install the drivers. Re-boot and see of this helps (going under the fact the boot order is correct).