This is the Kenny Rogers' version of Unforgettable which was originaly sung by Nat King
Although I like both versions I found Kenny Rogers' version more suitable for guitar.
intro in this version is played on keyboard. I may have left out a few chords but it 
doesn't afect that much.

Fmaj7                          E7
Unforgettable, that’s what you are
Gm7                           D9sus4
Unforgettable, though near or far
Cm7            Ebm7                   Bbmaj7
Like a song of love that clings to me
         Ab7           G7
How the thought of you does things to me
C9               Am7          C9
Never before has someone been more

Fmaj7                   E7
Unforgettable, in every way
Gm7                                 D9sus4
And forever more, that’s how you’ll stay
Cm7                  Ebm7            Bbmaj7
That’s why, darling, it’s incredible
      Ab7       G7
That someone so unforgettable
C9               F             Bb --- C# 7
Thinks that I am unforgettable too


---instrumental interlude---(one note higher)
Fmaj7#   F7  G#m7   D#9sus4   C# m7  Em7
7  A7   G# 7


C#9             Am#7        C#9 -- D7
Never before has someone been more…
Gmaj7                   F# 7
Unforgettable, in every way
Am7                                 F9sus4
And forever more, that’s how you’ll stay
Dm7                  Fm7             Cmaj7
That’s why, darling, it’s incredible
      Bb7       A7
That someone so unforgettable
Dm7             Fm7   G7       C-- Cmaj7
Thinks that I am unforgettable too

来源：www.ultimate-guitar.com