[Epic 4G General] bitbang3r:
The only two real possibilities might be WebOS and Meego, but even they probably have no real future unless they can encapsulate Android compatibility and offer something compelling that goes above and beyond it. WebOS might pull it off, but IMHO Meego is a lost cause, just because:

a) Nokia is its only real supporter,

b) Nokia has allowed itself to become almost completely irrelevant in America as both a brand name AND technology provider,

c) it's almost impossible IMHO for any hardware platform with basically zero mindshare in America to become more than a niche local product. America might be a small part of the global market in terms of units sold, but it's a very influential part of it. Nokia's fatal mistake was assuming that the sole value of the American market was the (minimal) revenue it made by selling phones to American carriers, while totally ignoring the staggering global influence of American media on the rest of the world. The outcome is something we've all seen... 5 years of "Smartphone Roundups" that didn't even mention the EXISTENCE of Nokia phones, and led to them becoming all but irrelevant among high end phone users even in their own home market: Europe. Nokia might try waving the flag and getting people to think Android is "too American"... and they'll fail, because it seems like at least half of Android's core developers are European (even if they live and work in Mountain View), and I don't think even Google will ever really be able to control Android's future global destiny once Chinese developers get tired of waiting for Google to fix things they care about passionately and just take matters into their own hands in ways that cause it to lose full compatibility with "mainstream" Android in ways that can't easily be reconciled.

It's not impossible that some other standard might emerge from China (unique in the sense that its domestic market is basically the same size as the entire rest of the world minus India and Africa, and most phones sold worldwide actually COME from China), but even in China, I'd put the smart money on either Android or a mostly-compatible fork of it. IMHO, China's contribution to our future happiness will be phones that are like PCs... more or less commodity hardware differentiated by speed, aesthetics, ergonomics, and niche peripherals that's perfectly happy running GoogleAndroid, a Chinese variant of Android, Windows*, or a slightly hacked & pirated copy of IOS. Phones sold by companies like Motorola and Samsung will be the equivalent of a micro-sized PC made by HP, sold at Wal Mart, ships with Windows, and nobody has ever successfully gotten Linux to work on because it uses some wacky proprietary video chipset that's undocumented and lacks drivers for anything besides the specific version of Windows that PC shipped with from the factory. Companies like Dell and HTC will sell phones intended for Android, but capable of being coaxed into other OS'es with a bit of work (like running Linux on a Dell Laptop today), and most of US at XDA will have phones designed and marketed by medium-sized companies that focus on trying to outdo each other with arms-race hardware based on bleeding-edge chip and circuit designs that looked good in cad, in the analyzer, and maybe even in the prototype... but inevitably have some major problem that didn't become obvious until 250,000 were made, sold, and bought by users who assumed the flakiness was due to rushed beta drivers instead of some deeper design flaw or premature attempt at cost-cutting that went a bit too far.