Me too. Raised in southern Ohio.
I forgot to say that I’m from southern Ohio, too.
I say it closest to the fourth choice but I say “RES - ter-ont” instead of rest - uh-raunt. That is when I’m not saying it " INNNNNN terestin’ " , Bugs Bunny style.
The second way. Grew up in Chicago, moved to Wisconsin, Indiana, and now back in Illinois. I think my way of speaking has changed (mutated) as I’ve moved around.
In my dialect (idiolect?) the reduced form is “lie-bri”. I think the Japanese English teachers even say it that way and they are sticklers for speaking with the correct number of syllables.
Here are the three pronunciations listed at dictionary.reference.com:
/ˈlaɪˌbrɛri, -brəri, -bri/
While I sometimes say in-truh-stingI really can’t think of saying the phrase “interesting restaurant” unless I’m accenting the first word. And, if I’m accenting, I’m going to use the longer form.
That doesn’t apply to restaurant, however. I just don’t hear the three syllable version as an acceptable version. I do always separate the first and last syllable, though. Rest-ront, not res-tront. I assume it’s to acknowledge the elided syllable.
I also entertain the idea that I like in-ter-rest-ting rest-ront better because of its rhythm. You can easily pronounce it as three trochees. Any other combination seems to produce two or more different feet.
ETA: Born and raised in northern Arkansas. And I’m 25.
Wow, I never realized how interesting the pronunciation of interesting was.
In this case, I said the first option, “in-ter-es-ting res-tront”. However, I say “in-ter-est-ting” and “in-tres-ting” pretty much interchangably. Restaurant is always “res-tront” unless I’m being purposely facetious.
Born and raised in south Florida, and I have a very neutral accent (formally, a Midwestern/broadcasting neutral accent (but my voice is not strong enough for broadcasting)).
Hey, my choice isn’t there:
Inta-les-ting Les-ta-lant
Any guesses as to where I’m from? 
Someplace that serves flied lice?
I chose 5. I say “in-ter-es-ting res-ter-ont”, with “er” not “ah” in ‘restaurant’. Southern Ontario.
I’m from the antipodes and I choose option 3 for normal speech.
“In-trist-ing rest-uh-ront” - I grew up in SE Michigan.
It is? I’m Australian and I chose #3.
I voted “in-tres-ting res-tah-ront”, but I think “in-tres-ting res-tront” is just as likely for me. I think it would depend on the context, and whether there was a reason to emphasize restaurant instead of interesting. Based on that, I might end up using any of the choices based on context. Lived in NE corridor almost all my life.
Well, I used to think my pronunciation of each syllable of “interesting” was stuffy, but given the results, I’m beginning to think that on this issue at least, I’m not so odd.
The idea for asking about “restaurant” came to me as I was playing Modern Warfare 2. There’s a level where you are told, in effect, to kill some enemies over at “the res-tah-ront.” The squad leader is black, and I realized that many of the black people I know pronounce it this way, while almost none of the Caucasian or Hispanic people I know pronounce it that way; it’s usually “rest-ront” for them. Of course, that’s just anecdotal and probably not indicative of anything, but I thought it might be a regional thing, so I asked about that.
in-ter-es-ting res-ta-ront
This is how you pronouce it in Strayn mate.
Like Onomatopoeia. Francophone.
Option 1. Anglophone Montrealer.