We were looking at Tioman island off the east coast but didn't eventually get there because of the monsoon. But that has all of those ingredients and more.
Alternatively, if you want something more adventurous, try Sarawak and Sabah on the island of Borneo. Amazing adventures to be had. about 8 years ago
For diving, I would recommend Redang Island. As far as I know the beaches there are beautiful. Or you could try Penang. Foodwise Penang and Ipoh are my top choices, that's if you want to have a taste of the local food. If you want to have access to what I call "branded food" such as Subway, Tony Roma etc., KL would be good. You could try Sarawak and Sabah as well for jungle trekking and sight-seeing. Hope this helped. almost 8 years ago