score:7
Malta is a place with a lot of places of historic and archeological values. It hosts the oldest free standing buildings in the world (Older than the pyramids!). These are definitely worth a visit. The countryside is scattered with pre-historic remains. There are several Roman remains as well, like the Roman Villa in Rabat (Domus Romana)
Other places worth seeing are:
I would suggest taking a look at Visit Malta for information about Malta, and Visit Gozo, a recently launched portal for information about the sister island of Gozo.
Upvote:3
I visited Malta nearly thirty years ago so this might be out of date. Malta isn't a large island, and you aren't going to find exciting sightseeing to keep you busy for two weeks. If you have a car, everywhere is a day trip from everywhere else. The Wikitravel page will give more details. Most of the places to see are in Valletta, with Mdina being interesting too. You might also try Saint Paul's Bay, the traditional site where Saint Paul was shipwrecked on Malta. However there wasn't much to see when I was there.