Are there any well known databases with real valued feature vectors and classification labels which people tend to use to test clustering? Particularly difficult databasets where error rate is below 80% would be nice.

I see alot of choices from the UCI repository, but I'm not sure which one would be suitable.

Are there any well known databases with real valued feature vectors and classification labels which people tend to use to test clustering? Particularly difficult databasets where error rate is below 80% would be nice.

I see alot of choices from the UCI repository, but I'm not sure which one would be suitable.