There is always going to be something sucking up time, yes, but there are some times that are worse and some that are better. One thing to keep in mind is that just the excitement of having a new game can usually carry it along for a month or two; after that is where the timing tends to be more important, because if the game is no longer shiny/new/exciting and there's something occupying your time, well. In my opinion, finals isn't actually so bad--it's a week or two, but then there's a break from classes, so it evens out.
Some of the worst times to start a game or to hit the two-month slump are November, because of NaNo, and August/September, because everyone's moving in and adjusting to a new school year. The better times in my experience to shoot for are December, May, or June.
Of course this is all my opinion and other people might think completely differently :)