Mark,

There's a fair bit to see but mainly it's the setting around Grand Harbour of naval interest.
I think the Maritime Museum is still being refurbished, but try to get to Fort St Angelo, Naval HQ during WWII The" Malta Experience" is worth it.

You can trace where the subs were based, where Illustrious was bombed, where the Ohio came in... lots of good books on the war and the Great Siege are on sale there, including some well-illustrated ones.

I used to go there on business regularly. My father was there in the war, told me the be sure to visit "The Gut.! It's definitely not what it was!

Enjoy the trip,

Craig