If I want to dual boot Vista with XP, what version do I need?

[Kaiju]

I have XP Pro SP2 and have already created a 25GB partition on my C: for when I buy Vista. Only trouble is I don't know what version I need.

I have a A64 3700+, which I believe is 64-bit, so should i also get the 64-bit version?

 

[daz.wallace]

Simple answer is yes, get the 64 bit version

 

[Kaiju]

Can I use the upgrade version when dual booting?