I almost always go by my full first name (Sandra). Not very exciting. Although I'm always surprised at how often people take the liberty of calling me "Sandy". Usually they are trying and establish some familiarity, while ironically making it clear that they don't know me at all. I don't know why, but I hate "Sandy" and I always cringe when someone calls me by that name. One time a car salesman (that was the embodiment of all car salesman stereotypes) called me "Sandy-land" - that did not go over well.
The only enduring nickname I've had was given to me by my two youngest siblings. When they were younger and couldn't pronounce "Sandra" they would call me "Cha-Cha" - and still do to this day. jb was not a fan of this, since when she came onto the scene the kids thought it would be hilarious to call her "Charmin" - as in the commercial jingle, "Cha-cha-cha, chamin!"
jb and I tend to call each other "love" or "my love". jb went by her last name for years - I guess it's a sports thing. Her dad calls her "booger" or "boo" and when she was younger "skooter" or "marusha".
Uncle Daniel goes by skippy, as per his request.
Leo gets every nickname in the book thrown his way. Monkey, short stuff, chief, kiddo, albondiga, bucko, enano, mister-mister, Leo-BO (this one we read on a baby-naming website. In the comments section someone named Leo warned prospective parents not to choose this name because he was tormented by children chanting Leo-BO - so naturally we call our son by this delightful nickname), chaparro, angel, chamaco, delicate flower... The list goes on and on, but the most common name for him is "Stinks" (or some variation: stinker, stinky, Mr. Stinkerson).
And finally, Talula goes mostly by Lulu, but if we are particularly happy with her she will get a "Lulabelle" thrown in for good measure.