After I had removed Vista again, it seemed that every time I rebooted, I got a BIOS screen which said 'Non system disk' or some shit like that, as a result of I had to power off then press the option key to bring up the list of bootable disks.
I checked the settings in startup disk, it was telling it to boot from my OS 10.5.1 disk, which should be correct.
So, I did a little bit of digging, and while OS X strictly speaking doesn't use the EFI partition, unless you are doing firmware updates, it can cause boot problems such as what I was experiencing if it doesn't exist. So....I checked out my EFI partition, which appeared to be either missing or corrupted.
So, not only had Vista been particularly shit, it had also decided to zap the EFI partition on my primary boot drive, which pissed me off a lot.
It was easy enough to fix, but hassle I didn't really want. I first made sure I had an up to date time machine backup, just in case I fucked it up. I then tried to repair the EFI partition in single user mode, which didn't work at all, the size of it was wrong, and it just wasn't having it. When I attempted to reboot after attempting the fix, it booted straight on to the OS X install DVD, which for convenience, is in a 10GB partition on one of the secondary drives.
When I fired up disk utility, it couldn't see the name of the system volume, it couldn't repair it, so basically my repair attempt hosed it completely.
Still, not to worry, so I erased it, and restored a time machine backup onto it, which completed in about 20 mins.