No, you want to install it in the order of XP, Vista, then Ubuntu. You could go XP, Ubuntu, Vista, but then it would require more work to get Vista's bootloader to boot Ubuntu, whereas Ubuntu's bootloader (usually GRUB) should be able to pick up on, and boot, both XP and Vista without any problem.
I think the Linux bootloaders overcame this problem, but I can't remember for sure. There's a limitation in the BIOS of pretty much all PCs that means you can't boot an OS where the bootstrapping code is beyond the 1024th cylinder. If memory serves, that works out to about the first 8GB of the drive. I'm reasonably sure Linux bootloaders can get around this, but you will probably want to do some research of your own.
Also be sure that the Linux bootloader is being installed into the master boot record (MBR) and not just the first cylinder of the partition as is often an option.
I would suggest using Google to find the Linux Documentation Project website, and looking through their collection of guides and HOWTOs. Vista is about a year old now, so there may well be a HOWTO on doing a triple boot with XP, Vista, and Linux. You can also check the Ubuntu forums where are pretty lively, and have some rather helpful people. Just be sure to follow proper etiquette and run a search for your problem before posting a new one.
My problem is that I want to have all three systems on my laptop. I install XP first then ubuntu. When booting back into Xp It dies for some reason. I belive ubuntu messes up the boot loader for xp. Do you recommend me install ubuntu first then installing xp, then vista?. I will partition the drives with the partitioner that comes with ubuntu. which is really easy. Should I place the windows partions at the starting of the hard disk or does it matters. Thanks in advance for and advice.!!!
ATI XPRESS 200M 256 MEMOREY
1.5 GB RAM
80 GB HARDDISK
INTEL CENTRION M PROCESSOR 1.73 GHZ
I AM PLANNING ON STORING ALL MY FILES ON AN EXTERNAL DRIVE.
SORRY FOR MY SPELLING!!!!!!