This is a question some of you might use in the topic. I personally can't get one specific sound out of my head.
And since there are probably more experienced guitarists up here, than I am, I guess at least someone could help me.
I've fallen in love with this soft sound and would really like to know what's producing it...
The guitar?
The amp?
or some weird effects?

http://www.youtube.com/watch?v=PSStufx6jYU

Please help!

I would say that it's a combination of the neck pickup, the vibratos that he did, a weird distorted synth type effect, the cheaper old amp, and the poor sound recording from that era.
but mostly the effect and neck pickup.
weird though... quite an odd effect.

i agree with Mike .... you will need lots of smooth sustain and good vibrato to pull that off