Lyne you need to go with 64 bit so you can use at least 8 gig of ram if you ever going to be satisfied with using Vue 6 infinitie.   XP pro 64 bit is what I am using and no problems at all with it and any the software I want to run with it.
 I am gun shy of Vista and it will be many long days and nites I hope before I have to install it. :)

I have a dual boot system with Vue 6 INf installed on Windows XP Pro 32 bit and also have it installed on Windows XP Pro 32 bit.
 The 64 bit lets me use the full 8 gig of ram where the 32 bit is only using 3 gig at max.  I can compare the two and believe me the 64 bit will blow circles around the 32 bit. :)

 I know its up to you what you want to install and do so don't take my comment as trying to tell you how to run your business as some like to do.  What ever makes you happy is what its all about. :)

ïÏøçö