I think taking Saraswati Puja as the Valentines' Day in West Bengal occur for those only who cannot enjoy Valentines' Day to the fullest. In fact school students have lots of problems on the Valentines' Day since lots of questions ("Where are you going in this much hurry?" / "Suddenly so well dressed today? Looks like you are going to celebrate Valentines' Day and not to private tuition" / "What will you do with money today" and so on) come a-flowing like arrows from seniors. With those throngs of gaily clad girls with shampooed hair roaming around, Saraswati Puja is really a divine day for boys in Punjabis and Sherwanis, and also vice versa.
Valentine's Day, I feel, is a little different and is best enjoyed by college and university students. They have some privileges like going out in any dress without clarification to guardians, a little heavier wallets, more lenience at home in terms of girlfriends and boyfriends, and so on.
To sum up, for me Saraswati Puja was the day to suddenly find your dream girl in the street and rush through the crowd to steal another glance, only to celebrate the Valentines Day few years later with a candlelight dinner in a cosy restaurant!