What is a good civ for playing defensively and making money?

Solution 1:

Rome is actually very good for this as one of their UUs, the Legion, can construct roads, allowing you to build and connect far-flung cities without the risk of Workers being captured by Barbarians. Send out a Legion with every Settler and have them build roads back to the capital once the new City is built.

If you're not the empire-building type, getting high gold income will be rather difficult as Brave New World has greatly reduced gold income from tiles to push you to use the new trade route mechanic. Arabia is most likely your best bet for high gold income without investing a lot in multiple cities. The UA allows your trade routes to extend further and the UB is one of the best, if not the best, for gold income. Given that you gain so much gold income from the Bazaar, it's best that you rush it as quickly as possible. Try to site your cities near oases and Oil resources (though the latter is pretty much luck of the draw until you get Biology) to get that precious +2 Gold per tile.

Note: since you mention playing with your friends, playing the Dutch can be useful as you can build Polders on your friends' territories. Remind them to not do anything to marshes and floodplains as the Polder is one of the better improvements.

Solution 2:

India is the main Tall empire. Their happiness modifier makes you want to avoid settling/conquering, but allows a lot of science to come out of the few cities you have.

Persia is what I think of when I want gold. Golden ages lasting longer means more gold from them.

Solution 3:

There are several good options for producing a strong economy.

Civilizations

• Ahmad al-Mansur, Morocco
  • Extra gold per trade route with other civilizations
  • Unique tile improvement (Kabash) adds gold to desert tiles
• Darius I, Persia
  • Golden ages last 50% longer (during golden ages, you generate more gold. Also, when playing tall, you are more likely to hit more golden ages.)
  • Unique building (Satrap's Court) gives more gold. Also allows you to hit golden ages more often by giving happiness.
• Enrico Dandolo, Venice
  • Double as many trade routes available
  • Unique unit (Merchant of Venice) replaces Great Merchant and gives you double gold for trade missions with City States.
  • Venice is extremely strong for producing gold, with the notable downside that you cannot build Settlers to claim additional land.
• Maria I, Portugal
  • Gets additional gold per trade route (based on how many different luxury resources you have)
  • Unique unit (Nau) can produce gold, once per unit.
• Pachacuti, Inca
  • Roads/Railroads on hills are free and half cost elsewhere. This means more gold per city connection.
  • Unique Improvement (Terrace Farm) can help you play tall even though you have a lot of hills and mountains in your territory.
• Pedro II, Brazil
  • Unique improvement (Brazilwood Camp) generates gold in jungle
• Wu Zeitan, China
  • Unique building (Paper Maker) replaces the library and generates gold instead of costing gold maintenance.

I have not played all of these myself, but in my experience Darius I from Persia is an excellent civilization for playing tall and generating gold. The golden age benefits can be quite significant for your gold output. Venice is a very strong gold-focused civilization, but it is quite a different experience than others since your only way to get more cities is through war or purchasing city states (with the Merchant of Venice) and even when you get more cities, they will always be puppets.

Other Recommendations

I also suggest founding a religion and choosing the Tithe Founder Belief. Especially when playing tall, you can get a lot of gold from followers in your cities and you don't need to actively spread your religion beyond your lands.

Barbarians are always a bother in every Civilization 5 game I play. Even when playing tall and not focusing on military might, you need to build a few military units and place them around the land near your cities. Barbarian encampments only appear in places that you cannot see, so spreading out some units so that you can see as many tiles as possible vastly decreases how many barbarians will come your way.