I dont expect Google to acquire big companies spending lots of money ...They are frugal and most probably they will look for small developmental stage technology/internet companies and most acquisations will be well below 100 million USD! ...Ok here are my few predictions!
1, I expect them to buy a small travel search engine ... "Mobissimo.com" has a good chance .They are a cambrian venture company whoose founding partners also happens to be stanford buddies of page and brin ...Their previous portfolio company kaltix was already acquired by Google!
2, They may want to increase their exposition in B2B where the margins are irresistible! ...First step will be to accelarate their corporate portal and search efforts ..."Plumtree" is a good canditate!
3, They may want to become a ecom technology platform like amazon or yahoo which will be a one stop solution for mom /pop type merchants ,providing everything from Website hosting/CC handling to traffic generation! ...Any good companies in this area?
4, Mobile Commerce? - May look for some small developmental stage company working on location based comparison shopping!
5, They may think of buying a small VOIP company ..."Skype" comes to my mind!
6, They may do one or two big (>100 million) acquisitions ..."Doubleclick" is a good choice and it will make them a full fledged internet advertising company overnight!