It had a lot of promise and there were parts that were good and a lot that made you roll your eyes. It wasn't a terrible, terrible movie, but it's not a classic either. I feel like in 20 years, we'll remember this movie like people remember the King Kong remake.
For me, it wasn't a straight adaptation of the book. It was Tim Burton's view of the book. I can't accept the argument that this one is closer to the book because apart from a few minute differences, it basically tells the same story. The Gene Wilder version is not so alien from the book: it's not like how Stanley Kubrick went 180 when making his adaptation of The Shining.
The one thing that killed the movie was that idiotic backstory (which WASN'T in the book for all you adaptation fanatics). It killed the pacing of the film, it weakened the mysticism that is the character Willy Wonka, and it just ruined the ending.
But I did like the Oompa Loompa songs if only because I like the Oinga Boinga feel to them...