I understand where you're coming from, saying that it's more special when it's unexpected and i can understand that it might put pressure on you guys, but if you're comfortable with the person you're with, both of your expectations are usually in sync so that no matter what you do together or for each other, it's special.
sure i think you should respect your sig other and celebrate your love every other day of the year, but valentine's day is an excuse to be extra mushy and flaunt it!