MonSound
You will never get any group of people (like us) to tell you what keyboard has the best sounds. It is entirely too subjective. What YOU might like, we might not. You have to listen and choose for yourself.
And, also, you will not find one keyboard that has what you consider "perfect" sounds in every area. It just doesn't exists. To do that, someone would have to take a Technic's piano, a Korgs string's, a Yamaha's flute, a Roland's sax, etc. and combine them into one. Sure, there will be one keyboard that you like much more than others. But not one that will be "perfect" in every area.
Tom
PS: If you like the 8000, I think the 9000 would be a logical step up for you to consider. But, you will LOOSE some features (and GAIN a lot). That is why some players still hold onto their 8000's.