I agree, I think Maui would be the best bet for what you want to do. I would only add O'ahu and/or Hawaii if you were going to be there longer than a week and wanted to hit more spots of interest.
I was born and raised on O'ahu so it's 'home' to me and my favorite island. However, if I was going to go somewhere just to 'relax' and play tourist then I would go to Lahaina, Maui
Lots of info on the internet on places to see there. Or you could take LuvMySissy's mom as a tour guide - she gave wonderful descriptions of fun places to go
And yes, go with a condo because the food and entertainment is very expensive and you can save money eating breakfast at your condo and even packing sandwiches and stuff for lunch and then treat yourself to dinners out