Gulf of Taranto

The Blue Guide to Southern Italy has one page covering the first three on your list, but it would give you an overview of the region. I think every region of Italy has appeal, but there is just not as much as in other areas--a museum or significant church here or there--but the parks of Calabria look spectacular.
I saw the temples at Metaponto. They are amusingly tucked behind a gas station just off the highway.

Cosenza and Matera are inland, so do you mean the Tyrrhenian sea, the Adriatic sea, or the Ionian sea? You'll find plenty on Matera.

Thanks -- actually, I was referring to the provinces of Cosenza and Matera, rather than the cities. The Ionian Sea coastline is where we'll be.

Gotcha--I greatly enjoyed the Matera area. We took day trips to Craco and Laterza and there's much more. I know less about Calabria, but I hope to get there one day.
Another good resource is tourism board websites, especially for the individual provinces, but alas I don't see a ton of great websites. Here is one: http://www.turiscalabria.it/website/?lang=en&categoria=/where/citta/&view_type=s&id=120&title=.html
Last, check European newspapers: https://www.theguardian.com/travel/2014/oct/04/calabria-italy-beaches-bars-restaurants-hotels
good luck!

I know the OP is not specifically asking about it, but of everywhere I have visited in Italy, I would say that the city of Taranto is the most depressing.

That said, it has an absolutely brilliant archaeological museum called MArTA.

I will make a point to avoid Taranto!

Taranto is the headquarters of the Italian Navy (and a famous Naval batle in 1940). It was the only colony settled by the Spartans and as such has quite a rich history. If you are interested in that sort of history (as I am) then the Museum is worth the trip regardless of the rundown nature of the city.

In all seriousness, I'm told the area around the railway station and walk up to the main city centre is not typical, and that "it gets better" - but I was genuinely concerned walking around parts of it - and I think almost nothing of walking in e.g Naples.

hey hey RobM
italyheaven.co.uk/basilicata or matera or any town you want in search bar
i like to use this site to learn and research about places i'm interested in
lifeinitaly.com under tourism

click area that interests you
wikimili.com/taranto
italymagazine.com/"untouched italy" basilicata & puglia
i also use this site to check and research places. hope this info helps you
have a great time and enjoy
aloha

It’s been a very long time since I went to Taranto as a guest bod a friend from my “service” years.
In Taranto see:
CITTÀ VECCHIA and SAN CATALDO (cathedral)
CASTELLO ARAGONESE
PONTE GIREVOLE
Outside Taranto:
CARAIBI DI PUGLIA (beaches)
SAN PIETRO IN BEVAGNA (beach)
MARTINA FRANCA (whitewashed village)
GRAVINE DI TARANTO (terra elle Gravine park)

Google the above to see.