It's my second favorite of Connery's, right after
From Russia With Love. At least my 7th favorite overall. When the modern day Bond drifts into larger-than-life spectacle, I always wish it would be more like
Thunderball and less like
You Only Live Twice or
Moonraker. Those other over-the-top Bond movies have their charm, but none keep themselves
just grounded enough like
Thunderball does.
I also find it the funniest Bond movie. There are some cheesy lines, but on the whole it's smartly written. In particular, the Q scene might be my favorite in the entire series, but in general the banter between characters strikes the right balance between believable dialogue and 60s camp.
Then you have one of the most underrated (yet most duplicated) Bond villains in Largo, the most gorgeous Bond lady of all in Domino, and of course it's set in the Caribbean which might as well be Bond's home turf instead of England. Excellent soundtrack on top of everything.
If you have a home theater system and a copy of
Thunderball in high-def or Blu-ray, or know someone who does, it could easily become your favorite Bond movie if you're not careful. And by that mean it almost takes proactive, stubborn adherence to others as your favorites to not have
Thunderball casually dethrone them, as casually as Connery glides (and I mean
glides) through this one.