XP Pro vs Vista

In the end it is your choice.
Just one small thing to remember, Windows XP will not be supported in the near future, so if you need any of the service packs then down load them in the ISO format so as to burn them to dvd. Do not use cd because this disk will be too small for the service packs.
I have used Vista for over a year now and have no problems at all except where i am testing out software, some software tends to ball's up the system. Any software you have that runs under XP will run under Vista as long as you run it under the compatibility section.

Until Windows7 is released.

By most accounts it is an improvement on Vista and due for release in the medium-immediate future.

The other's that have replied make good sense, but allow me to add my $650 billion. If you purchase your new computer at the local computer superstore, you are most likely going to have one choice..VISTA. If you go directly to the manufacturer, such as DELL, you will have a choice to purchase the PC or NB with XP Pro, but only after you add an additional $100 to the price. It will come preloaded with XP Pro, but you will also receive the install disks for VISTA. You can then LEGALLY install VISTA and use it if you ever decide to. You could save yourself the $100 and purchase the computer with some form of VISTA Business and then LEGALLY downgrade to XP Pro. To do this, you would have to find the appropriate OEM XP disk as it will not be provided at purchase. I just recently installed VISTA Business x64 on my laptop and am impressed that it seems to have more available drivers than the previous XP Pro x64 that I was using. As an IT Consultant, I decided that this was a good way for me to become more familiar with the ways of VISTA.
Before you make your decision, you might want to research if any of the applications you use are VISTA compatible. I have learned that just because a vendor says their product is, doesn't necessarily mean it's true.

My experience's with Vista... I was forced into it when I purchased my laptop, and this was before SP 1 came out... it was really bad! However now, I have upgraded most of my PC's to vista and I love it. My gaming rig has Vista Ultimate, laptop has home premium vista, and my media center has Vista home premium also.

All of them run great, I have no complaints anymore about the OS. Just as a fyi, my media center has a 2.0 GHZ AMD (Socket A) processor which is really old, One gig of DDR RAM, and a AGP 8x ATI HD 2600... the PC is as snappy as the day I loaded the OS. It is a little CPU intensive... and RAM heavy, but if I didn't keep a close eye on things I wouldn't have noticed...

Also I ran some benchmarks Vista vs XP... on my old gaming rig (recently built a new system) about the middle of the page are the results if you want to check it out. https://www.techrepublic.com.com/5208-6230-0.html?forumID=102&threadID=281262

But if you do not use it, you can not really comment on it can you.
I test new operating systems out, it is my job to do so. It gives me a heads start of what is wrong and right with the system(s). Doing this brings more information and knowledge. It is like travelling, you see something new (code), hear something new (language and settings). If you stay in one place (and never venture out) then you are only going to gather up dust and be left behind with your old cranky, smoking, and rotten/rotting machinery of yesteryear of which will be sooooo old that you will have to either go for a Linux rescue or a fully fledged Windows system. Windows 7 will not be ok as of yet, but i will be testing it out, i have tried the BETA version, but at the moment, it is a bit loose with the coding for the drivers, but i am working on it.
AND no i do not work for Microsoft, just in case you go down that road. But i do sent info to them (Microsoft) about the troubles.

I recently purchased a new bankrupt stock computer. It has a Celeron 432 and came with Vista Basic. I added Memory to 2GB and I really love Vista. If you are just using Office, a photo application and video work then Basic copes admirably. I see no need to upgrade to Ultimate as everything works just fine.
I have been using computers since 1070 so have seen all manner of advances and have stuck with Windows throughout. With Vista everything just works and it is much better than XP pro which I have used for the past 7years after 2000 pro.

Just make sure you get to relearn Vista after xp as there are a few minor differences. I find it faster, more stable and much more secure.