How to file taxes? confused..?

im married, has one job as a nurse.. my wife is unemployed since 2007, she was self-reviewing for the nursing licensure.. just took it this year and ped.. she's now pregnant with our first child.. we filed jointly last year even though she didn't have any income.. does she really have to file for taxes? should we file jointly again this time?.. how should we file to maximize our refund? thanks!