My wife is Cuban, from Holguin. Cuba is a great place to visit, very different (no mcdonalds e.t.c!!). Make sure you make the effort to travel outside the usual all inclusive hotels because Cuba is quite a safe place to travel around outside the main resorts, if you speak some spanish it's useful.
There are some towns you can visit near varadero like matanzas but try to go to Havana for a couple of days if you get the chance. Loads and loads of hustlers in havana though, so be on your guard!! Not in a dangerous way, but trying to sell you dodgy cigars e.t.c.
We never go to Cuba in July/August, because it's just too hot. So you'll be in the right place by the beach!