I'll get these categories out of the way early because there simply is no logical way to go about predicting the nominees until the music has been heard. For Best Original Score, it isn't unreasonable to just pick Best Picture nominees or films with notable composers.
I get the feeling Alexandre Desplat was real close to winning this year for The King's Speech, but it ended up going to Reznor and Ross, whose work was more deserving anyway. Besides, Desplat will have many more opportunities. He scores so many films a year it's hard to keep count! He already has four lined up for 2011, including Terrence Malick's much anticipated The Tree of Life.
John Williams hasn't been nominated in a while (2006 for Memoirs of a Geisha and Munich), but he's got two Spielberg films to garner him some attention from the music branch, including possible Best Picture contender War Horse.
Could the elegant tones and orchestrations that helped Dario Marianelli to nominations for Pride and Prejudice and Atonement (which he went on to win) help him gain some traction for Jane Eyre? The early release is a hindrance, but sometimes a film from the first half of the year can survive it to the nominations.
Were it not for his Oscar-winning score to Up last year, I think Michael Giacchino may have still been in the running for his work on Star Trek. He's got another chance this summer to get our pulses racing with J.J. Abrams Super 8, which has many a movie fan shivering with excitement. If not that, maybe Cars 2?
James Newton Howard is still waiting for his first Oscar after eight nominations, the most recent of which came two years ago for Defiance. He's got a few titles in the running this year, including the adaptation of the bestselling Water for Elephants.
Predicted five:
Jane Eyre
Super 8
The Tree of Life
War Horse
Water for Elephants
Best Original Song is anyone's guess. Who knows what films will have songs? Animated features often feature one or two, so I suppose I'll guess:
Cars 2
Happy Feet 2
The Muppets
Winnie the Pooh