If you're planning on purchasing a new PC with XP preinstalled, do it before the end of the month. June 30th marks Microsoft's end-of-availability deadline for XP, but some OEMs plan to still ship PCs with the aging OS by taking advantage of downgrade rights built into Vista's Business and Ultimate flavors. However, buyers of Dell's Vostro line of desktops and notebooks will pay a $20 to $50 premium for the downgrade compared to just sticking it out with Vista. This begs the question, how deep (in your wallet) is your devotion to XP?