Microsoft have set the recommended retail price for its first-party Xbox One games at £49.99.
Close to current Xbox 360 RRP prices, it's expected that retailers will set pricing for Xbox One games very close to Microsoft's recommended figure.
Note that these prices are for Microsoft's first-party titles, including Forza Motorsport 5 and Kinect Sports: Rivals, and that other publishers may choose to suggest lower, or indeed higher, RRPs. FIFA 14 for Xbox One, for instance, currently has £54.99 pre-order price on Amazon for instance.
Keep in mind however that, at a new console's launch, competition between publishers is particularly cutthroat - you're not only asking consumers to empty their pockets for games, but for the console hardware itself. It's a pricey investment, and lowering the RRP can be a good way of securing a few extra sales from cash-strapped gamers.
Despite games being up for pre-order, Sony have yet to set an RRP for their own first party titles for the PlayStation 4. Microsoft's announcement will undoubtedly influence Sony's own move.