Are cruise ships a good thing for a city?

Cruise ships bring a lot of money to a city in the form of tourism and port taxes etc but is a large number of cruise ships always a good thing?
I'm thinking about this after having just read a report about Barcelona which so far this year has been visited by 355 cruise ships, bringing in a total number of cruise passenger tourists of over 1,000,000!
Now Barcelona is a big city and can cope with that number of tourists, (the pickpockets and thieves preying on the tourists of Barcelona being a separate issue), but I'm thinking of the small Caribbean islands, or the small Fjord village ports that play host to the likes of Allure of the Seas or P&Os Ventura and Azura.
When these ships come into port the population of these places can sometimes double and that's assuming only one ship is docked; most experienced cruisers will be able to tell you nightmare stories about two or three big ships being docked at a small port at once. Whilst there's no doubt that these ports benefit from the revenue that level of tourism brings I can't help thinking what happens the day after when there aren't any ships in and the residents need to clean up after 2,000 to 3,000 cruise passengers, or what happens when in the off season if the ports don't get any cruise ships visiting them at all. What happens to all the jobs created by the ships visiting and the people that depend on them?
What do you think?

Happy cruising?

The QM2 - I can't wait!

Just a quick one today to let everyone know I'm off down to Southampton at the weekend to board the QM2. It's just a short cruise over to Cherbourg so I'll be back by next Wednesday if you need me.
For all you hardened Cunard fans I'll try to get a review written by about Thursday, Friday time next week so check back to see all my pictures and see what I thought of her, (never been on the QM2 before, so I'm quite excited).

Happy Cruising