Do whatever works for you. For me I will prob have a table like all the other tables. Although the bridal party might sit at the table with us, since they are all married couples and our closest friends.
I too like the idea of a sweetheart table because I would like to have our time together as we eat, and then go and mingle with the guests. I prefer to have our wedding party sit with their dates because I think it will be a lot more fun for everyone including their dates/significant others. I personally don't see the point in a head table other than to force your wedding party to sit and stare longingly at the tables their dates are at and forcing the dates to be miserable during dinner.
We're doing a head table, but all of our bridal party's dates are sitting with them at the head table. So I don't know if that really counts as a head table. I think the coordinator referred to it as a "harvest table".
I wouldn't want to be separated...I'd want people coming up to us and talking to us at our sweetheart table.