Please don´t stay in a resort like Varadero. If you want to have an amazing time and also see what Cuba is really all about the best thing to do is stay in a casa particular in Vedado or Habana centro.
I recomend
http://havana-house.webcindario.com/
The casas are extremely comfortable and the owners are amazing, You will also get to see the ´real´Cuba. Alternatively you could alternate..a few days in veradero with a hotel/casa particular in La Habana, it really depends how long you are going for. I think you will have the best time in the centre though. There are some great clubs/shows around vedado and central Habana such as caberet national, la casa de musica, el cafe del jazz etc..
Enjoy! :-)