Although Malta is a small island across which you could drive in a few hours, it offers enough sights and activities to fill at least a week of your time.
I visited in Spring, which I found the perfect season to visit. Varying between 15 and 25 degrees, the temperatures are high enough to feel on holidays and wear your funky Summer dress, but not too high to stay tied to your hotel's airconditioning. Summer season hasn't officially started yet, so there aren't too many tourists around. But the decisive argument is without a doubt that in Spring, nature is at its best. The foliage of the trees is still green and the grass fields are scattered with blossoming, colorful flowers.
We had 7 full days to spend on Malta, plus the evening of our arrival and the morning of our departure. For us, this was about the right amount of time to visit Malta properly. Although our day programmes were quite loaded, I think we visited almost everything you can visit. There were some places which we checked out rather quickly but where we could've stayed longer if we'd had more time. If you'd ask me, I'd say around 10 days is the ideal amount of time to see the island properly and include some time to take it slow and relax as well.
Public transportation is quite limited on Malta. There's buses, but they don't go often and they certainly don't go everywhere. That's why many travelers decide to rent a car during their stay on the island. We didn't, but thanks to our excellent hitchhiking skills, we got around easily too. We were also lucky that our Couchsurfing host and our Maltese friend both offered to take us on day trips by car. Although a car makes it easy to get around, it is definitely possible to do so without. But if you do have car, make sure to stay away from the main roads around rush hour. Traffic jams take forever!
More elaborate articles will follow, but here's a suggested week program for Malta.