No real valentine traditions here other than the preschool/grade school parties, BUT many years ago I had a 1st grade student who was all excited because at his house they did a dress up fancy candlelight family dinner at his house for Valentine's Day. I thought that was a great idea. We ended up doing that tradition, but on our anniversary each year for a long time when we had kids. (Since our anniversary was a few days before Christmas we had agreed from the get-go that it would always be a family celebration and we'd go out alone after Christmas at least until they got older.) I'd say we kept the formal dinner at home on our anniversary, complete with wedding cake, up until they were in about 2nd/4th grade.
Since we aren't eating out right now, maybe I'll reinstitute the fancy candlelight dinner at home for just me and DH this year for Valentine's Day. Formal, dress for dinner, occasions aren't anything we would do at home usually and, since we haven't had company, my nice dishes haven't even seen the light of day in a year.