I believe The Beatles: Rock Band came the closest to being perfect. Eveything about that game was just beautifully done and the only things missing was Pro Drums, an option for Keys, and a few more Beatle songs (Hey Jude, Strawberry Fields Forever, Yesterday etc. etc.)
Perfection is overrated. Most of my favorite gaming experiences are with games of which I would be able to cite plenty of flaws.
I like games with sharp edges.
That said, there are a lot of good games being mentioned in these comments.
What’s a favorite example of a game you love in spite of genuinely painful sharp edges?