Let's not forget the words of Carly Simon -- "Baby, you're the best!":
(Not a great Bond film, по-моему, but the song was one of the greatest "Bond themes".)
Of course, you don't have to use the word "baby", but "Thanks, you're the best!" is a good colloquial way to express a strong спасибо when someone has given you a very nice gift, or has shown you great kindness.
Another way to express VERY strong thanks is "I'm blown away (by your kindness, by your thoughtful gift, etc.)" or "This (kindness, gift, etc.) blows me away" -- the basic literal meaning is something like "меня взорвало, как будто бомбой/гранатом-ой" or possibly "меня унесло, как будто ураганом".
But you can use "Thank you, I'm absolutely blown away" or "Did I like your gift? Oh my god, it blew me away!!" to express the meaning "I feel such enormous gratitude and happiness that I have no words to express it."
Edited: Oops, взорвать гранатой (fem.) means "to blow up with a hand-grenade", but взорвать гранатом (masc.) means "to blow up with a pomegranate"!!