This is a matter of religious debate, of course !
If you want to hear the Linus himself say how he pronounces it download
english.au or swedish.au from ftp.funet.fi (in
/pub/OS/Linux/PEOPLE/Linus/SillySounds). If you have a soundcard or the
PC-speaker audio driver you can hear them by typing
cat english.au >/dev/audio
The difference isn't in the pronunciation of Linux but in the language
Linus uses to say hello.
For the benefit of those of you who don't have the equipment or
inclination: Linus pronounces Linux approximately as Leenus, where the ee
is as in feet but rather shorter and the u is like a much shorter version
of the French eu sound in peur (pronouncing it as the u in put is probably
passable).
When speaking English I pronounce it Lie-nucks (u as in bucket) --- this
is an anglicised pronunciation based on the analogy with Linus' name,
which in English is usually pronounced Lie-nus (u as in put). It is of
course quite acceptable and common to modify the pronunciation of a proper
noun when it changes languages.
I think I can safely say that the pronunciation Linnucks (short i as in
pit, short u as in bucket) is wrong in English, as it is not the original
Swedish pronunciation, not a sensible direct anglicisation of it, and not
based on the anglicised version of Linus' name.