Nice one, cheers mate! Really excited now!
We're staying at Be Live Los Cactus in Varadero. It's got massive pools and tennis courts etc. Apparently the food is a bit rubbish but that seems a consistent complaint in Cuba. We'll deffo be doing the classic car thing at some point in Havana.
Antigua & Spain with the family sound like two great holidays to me. Enjoy! I'm the same as you, love scanning through this thread, today of all days. 
I have to agree with Buck Pete about Havana. We stayed at the Iberostar Varadero while we were in Cuba and loved it. To be honest, the Varadero peninsula is not the real Cuba. It's basically just a tourist enclave, but the actual town of Varadero is more authentic. There was a bus that ran down the peninsula to take tourists into the town and back again when we were there.
The food in Cuba is generally quite bland. We were there for two weeks and it took me a while to adjust to it. Because there are few places to eat out, most hotels are all-inclusive in Varadero, and although the variety of food looked amazing, the actual taste was quite bland. As you say, it's something Cuba is known for. Being basically cut off from the rest of the world for so long means that the standard of food are not as we know them in most of the western world. Mind you, when I'm tucking in I'm always aware that we are having a feast every day there compared to the locals.
If you like a day out on a boat, a little snorkelling and a trip to a nearby Island then I know they do suchlike from Varadero. We went on one to Cayo Blanco. We had lobster and Cuba Libre on the way, had a snorkell out at sea, landed on the white sand island, had more snorkelling then drinks and a meal. It was a great trip.
If you'd like to visit a grand house / restaurant on the Varadero peninsula then there is the Xanadu Mansion, which used to be owned by the Du Pont family. We had a fantastic birthday meal there, and it's a lovely place right on the ocean. In Varadero town there was also a house that was owned by Al Capone. When we were there it had been turned into a restaurant and had a big gangster-style car outside. Again, this is on the ocean. If any of there interest you, it might be worth checking they are still in business.
Havana? Well, it blew me away. Havana, and the real Cuba in general is the most authentic place I have ever been to in my life. It is a living, breathing museum. Much of it is crumbling, but it has such a staggering beauty in so many ways. I know some people love Cuba and some hate it, but to me, if you 'get it' then it's magical. We booked a trip where we had two days in Havana with a one-night stay in a hotel in the new town. Day one was a guided tour around old Havana. I'm not too fond of these kind of things but in hindsight it was invaluable. You get to know so much about the place and can ask anything you like, so you have the heads-up for what you want to do on your free day on day two.
We managed to fit a lot in. We drank Mojitos at Ambos Mundos, the hotel Hemingway was resident at when he wrote some of his books. They still had his typewriter and, if I recall correctly, his room preserved. We sat there having cocktails whilst listening to the guy playing the piano by the bar. Horse-drawn carriages going past outside. It was like living in another time. Another great experience was bombing it down the Malecon in a Coco taxi to the Nacionale Hotel. This hotel is really grand and has seen world leaders, Che Guevara and numerous world famous stars stay there over the years. It's a great visit, and having Pina Coladas in the grounds overlooking the ocean is amazing. We then took a classic old American car ride back to the old town. We felt like stars too, in this amazing big open-topped car with red leather seats, cruising down the Malecon.
If you like architecture there is a lot to see. The Catedral De San Cristobal, The Gran Teatro, which is home to Cuba's National Ballet and Opera, El Capitolio, which is very similar to the Capitol Building in the US. The Museum of the Revolution, and Revolution Square is also worth a visit simply for the historical context. We also spent time at La Bodeguita Del Medio, a bar frequented by Hemingway. Take your marker pen if you go there. Writing your name and where you are from on the walls is encouraged. A night time trip to the Tropicana is great if it's your kind of thing. Spectacular costumes and dancing in a big, outdoor venue. In the day, the big outdoor market is a good visit too, if you like that kind of thing. We fitted all this and more into just two days and a one night stay. Taking your camera is a must. There is just so much to see, and if you are into photography at all, it's a place to savour.
All kinds of trips can be booked if that floats your boat. We did a full day trip to Santa Clara, where Che Guevara's mausoleum is and a crucial battle took place in the revolution. You can see many of Che's possessions inside the mausoleum building, though taking photos inside was banned when we were there. The rest of the trip took us to Trinidad then onto Cienfuegos. On the way we'd see old sugar plantations and people getting around on horseback. I'll never forget the school children out in the country going to school, all dressed immaculately and sat in horsedrawn carts.
Ah, I could waffle on forever about Cuba. Initially, I didn't quite 'get' Cuba, but once I did, it blew me away. As I said, if you get out and about, particularly to old Havana, it's like experiencing a different time. It's like walking around a living museum.
I really hope you love it and enjoy every moment.
EDIT: Sorry that is so long. I got carried away.
