I recently slowly bought my way up to 2500 shares of Citigroup. The fluctuation is tough to deal with, but I just ignore the day to day.
Most likely any bank that has made it this far is not going to go under now, and when the economy recovers (which will happen EVENTUALLY) this stock might hit $10-$15 dollars. Cramer the stock analyst said that he expects citigroup to hit $20 by 2012.
But you have to have a tough stomach!!! Ignore the day to day and week to week swings. If you panic and sell, then you will miss the big upswings