Yesterday, Microsoft inadvertently released the pricing of its upcoming OS called Vista on their Canadian website. The prices were picked up by the NeoWin blog and are also neatly layed out at Wikipedia.
Vista Home Premium will retail for $239, with upgrades available for $159. Additional licenses will be available for discounts as well. Vista Home Premium edition has evolved from XP Professional, Media Center, and Tablet product lines, and probably is also the edition which can most closely be compared to Mac OS X.
Many comparisons have been made between Vista and Mac OS X, and with many expecting Apple to continue its pricing tradition of $129 for Leopard (Mac OS 10.5), further comparisons can be made on price as well.
All prices in USD
Update: Amazon has Vista available for Pre-order at the above prices.