Right, so the thing is this. If you want a more robust operating system you have to have something run it. Just like if you want to add a bigger graphics card, you have to have a bigger power supply. Windows Vista is more robust than windows XP. Like it or not, someday you will need the robustness it has to offer. Even if you skip it and go for Windows 7, you’re still upping the power demand. Plus, Windows 7 will inevitably start out just like every windows OS.. buggy.
Seriously, if you have the hardware, go get Windows Vista now. If you’re still a student here you can get Ultimate for $10, but get it now because the budget cuts aren’t looking good to support that next year.