Defenitely both are nice and soothing.. As Mr. Pradhan puts it Promotion gives you prestige outside the official soceity also, where as salary hike is something that is known to you alone.
I believe 2 year is a good period to ivaluate an employee and he/she deserves a promotion if the performance levels are achieved. Its a very comlicated situtaion these days for most of the MNC's. There are a bunch of massive performers around and at the end of all the management is confused with whom to promote and whom not to. So few gets lucky with promotions and other gets settled for a heavy pay rise.