Looking for a new cell phone? This is the week to start taking notes for your wish list.

The world’s largest smartphone carriers — apart from one Cupertino-based exception — are gathered in Barcelona this week to show off the latest and greatest in their product lines for the annual Mobile World Congress.

And what a slew of announcements it is. On Monday, Nokia announced three new Android phones that represent a significant shift in the phone-maker’s strategy. It also throws down the gauntlet, to a certain extent, for the firm’s future owners: Microsoft. Nokia has been Microsoft’s marquee phone-maker. In fact, as of late, it’s more or less been the lone major manufacturer making Windows Phone devices.

The new Nokia phones are called the X, X+ and XL. The 4-inch phones are able to run Android apps but are not linked to Google’s Play store.

Instead, the phones are designed more as hybrids: They will get apps from the Android Open Source project and have tie-ins to Microsoft services. For example, buying a phone will also get you a month of free calls on Microsoft’s Skype. It also links in with Microsoft’s OneDrive (formerly SkyDrive) and Outlook and uses Nokia’s Here maps and Mix Radio.

With the deal between Nokia and Microsoft all but finished, it will be interesting to watch how the smartphone maker’s new parent company sets the future of the Nokia X line. If Microsoft is more focused on providing services across phone makers, the X may stay. If it’s more interested in making its own devices, the line’s future is more up in the air.

Nokia’s announcement isn’t even expected to be the largest announcement of the day. That prize will likely go to Samsung, which has planned a major press event that many expect to show the first glimpse of its new flagship phone, the Galaxy S5.

Samsung, still sitting pretty on top of the market for new smartphones, has cautioned of slowing sales for its top-end smartphones. But it’s important for the firm to have a flagship phone to set against the likes of Apple’s latest iPhone.

The Korean tech giant already made some announcements related to its product line, taking the wraps off of the second generation of its big wearable experiment in the form of a new smartwatch.

Samsung’s first watch model, the Galaxy Gear, debuted to tepid reviews at best, but the firm did say that it shipped at least 800,000 devices, beating analyst expectations. The new versions, known as the Gear 2 and Gear 2 Neo, look a lot like the previous version but run Samsung’s own Tizen operating system rather than Google’s Android. The Gear 2 Neo also comes without a camera — the Gear 2 , like its predecessor, still packs a camera — which may address some complaints that the first watch was too bulky. Both phones pair with Samsung’s Galaxy line, though not with other smartphones.

Not to be outdone by the competition, Sony and LG also released new smartphones and set goals for their companies in the coming year.

LG debuted two new premium smartphones -- called the LG G Pro 2 and the LG G2 mini -- for the higher end of the market, as well as a new line of lower-priced phones aimed at emerging smartphone markets. The company said that it’s aiming to provide a more consistent experience across its devices.

Sony is also looking for a little more unity, not only across its varying tiers of devices but across its whole company. Chief executive Kazuo Hirai has said that he wants the company to become “One Sony” and to find smart ways to combine Sony’s many products into good experiences for its users.

To that end, the firm’s new devices — the Xperia Z2, Xperia Z2 tablet, Xperia M2 and SmartWear fitness band — tap expertise from the firm’s audio, display, camera and content divisions.

Ovum analyst Nick Dillon said that the product line from Sony shows early signs that Hirai’s strategy is working.

“Mr. Hirai has finally managed to make Sony worth more than the sum of its parts,” Dillon said. “It is crucial for Sony to be successful in mobile, and it needs to continue to prioritize this over its other businesses.”