Oddly enough, I’ve had a long-standing fascination with the Falkland Islands. I think I could happily settle into Port Stanley or one of the “camps”.
SS
Yes. An island you can drive to isn’t an island. It’s been castrated.
When I started to read the OP’s post I immediately thought of Australia because small islands turn me claustrophobic after one day.
So I choose Sardinia (24’000 km2). From there I can take boat trips to the Baleares, Capri, Malta, Cyprus, Crete and all the Greek islands. That would keep me busy for the rest of my life.
And the climate is perfect, the language no problem.
Going to Tahiti with your wife, Arnie ? She would get suspicious of your activities in no time.
My first requirement for my island paradise is; no hurricanes. I would hate to spend one of my months off island just to evade a hurricane and then have to come back and live through the aftermath.
Secondly I don’t want to have to deal with tsunamis so I would at least want an island big enough that I can go to the other side and avoid them. I’m think that the island would need a minimum maximum elevation over 300 feet.
Third I want to be warm. I dislike winter and if I want to go play in the snow I can always use one of my months to go skiing. On the other hand I hate to be hot so I would want to find an island with a yearly minimum temp over 45 deg and yet a maximum in the 90s.
The last thing I want to the ability to be connected when I’m not laying on the beach sipping rum so I need to have good to great internet access preferably through cables but I’ll take high quality satellite access if I have to.
Of the top of my head I’m thinking one of the Hawaiian islands would work probably Maui or Kauai.
What’s the weather like on the Isle of Man? If I can’t have Ireland, I want something with a similar climate. In other words, nice and cool, never too hot, never too cold. Plus, close to lots of cool places. Also, really cool flag!
By your parameters, many people who have “enough money to retire” already live like this on the island of Manhattan.
In fact if I could interpret “unlimited 5-day trips” with “unlimited 5-day-or-less trips”, as in day trips, then I would do that in a heartbeat since Long Island (including Brooklyn and Queens or even Staten Island) would be open to me as well as Manhattan. I could live with only going further than that twice a year for up to a month at a time. Sure I’d miss my friends in Jersey or upstate, but they could come visit me in my penthouse duplex or mansion out in the Hamptons.
Hey, who set himself on fire to spark an insurrection that ended up with you as the OP? 
If this “other island” is also subject to this “no bridge or tunnel” tack-on limitation of yours, then I would not particularly want to be marooned on an island for 5/6ths of the year, even a beautiful and tropical one, even for “retirement level” funding. I would go nuts. I’m doing just fine as I am now, so I would pass.
Able was I, ere I saw Elba.
This.
And no marlin would be safe.
I wanted to mention that Sarkhas been named a Dark Sky Island, so if you’re into stargazing, you may want look into it (or above it). It’s also close to France and the British Isles for shopping. It’s a little on the small side though.
Well, if the choice is working vs. retiring on an island, not a hard dilemma. The only dilemma is: which island do you pick?
The reason I would pick Switzerland is not because it’s the best place in the world to live in (though for me it is!): I pick it because most of my family lives there, I have two young kids in grade school and Switzerland has excellent schools, they would have lots of opportunities, and it is a nice place to live anyway - you can live in a small remote village but be only a half-hour away from a semi-large city.
Islands are nice. The big drawbacks of the island life are if you are the kind of person that likes the amenties of big-city life, like live performances: theatre, opera, classical music concerts, big-name rock concerts, etc. You won’t get any of that on an island.
I don’t know if I would be as harsh as that :eek: , but my hypothetical billionaire is going to draw a hard line and say that if you can drive off it with a car, or walk off it at low tide, it’s not really an island.
Several great ideas in here that never would have occurred to me! I especially like the Zealand idea, or Sark. If I lived on Sark, I wouldn’t be there for six months before I tried the Clameur de Haro.
Is this the kind of thing you’re referring to? 
A friend of mine had a favorite expression that he used to annoy his wife when he went on business trips to Italy: bringing your wife with you to Italy would be like going to France and bringing your own bottle of wine.
So taking the train off the island – e.g., Manhattan or my idea of the Isle of Dogs – is right out?
Majorca is about 3600km[sup]2[/sup]; it’s the biggest island in its archipelago and within relatively easy reach of several other islands which also fulfill the OP’s conditions. Nice climate, nice beaches, I speak most of the local languages (ought’a brush up on my German), a good cultural scene and nice places to visit both there and in the rest of the archipelago… there are several companies there who might be terribly happy to retain me as an occasional consultant (yeah yeah, you said I had enough money to retire: that doesn’t mean I want to, having something that kicks me out of the house occasionally is nice). I think I’d be more comfortable with the everyday lifestyle there than in the Canary Islands, any of which would also be acceptable. Oh, and there’s cable internet in both archipelagos.
While “island syndrome” is quite common among “mainlanders” living in Majorca, the conditions posited in the OP seem enough to be able to stall it. I could always use one of those 5-day trips to visit… ok, not Sicily, but Capri or the majority of the Greek islands (I’ve only been to Crete).
Yup, kinda hard to beat Coupeville - I call dibs on the old Ebey place on the bluff, though!
Hawaii or Australia. … and I dont think "condemned" to live in Hawaii or Australia for 10 months of the year is the right word. LOts of people live there for 10 months a year.
Uh, got news for ya: They get hurricanes.
I’m no geographer, but isn’t Australia bigger than Sicily?
I am not a geographer either but I think it was a typo. I think he meant Austria.