Sliema is a great base for Malta. You won't see any Chavs and its a good place to take a girlfriend.
If you just want sunbathing and nightlife its great but there are other places. But if you like sightseeing and History as well you can't beat Malta for that.
Valletta is an gem of history and...
Where is it.
At night Sliema or Paceville is the best place - nothing to do in Valletta at night so save your taxis fares
Best Beaches are in the North where there is more sand. Beaches around Sliema & St Julians are rocky.
Only place which might be a bit Chavvy is Buggiba / St Pauls but its...