What should you hear?

Listen to a well recorded symphony if you want to experience good imaging and soundstage. There is width and depth with each section of instruments placed correctly on the stage. 
With a large orchestra you can hear that the string section forms a semicircle, the wind instruments are centered behind them, percussion in the back, etc.

I accidentally stumbled onto the chalet way up on Red Mountain in Aspen where Dave Brubeck and his group would go to hang out. Brubeck’s concert grand piano was hooked up to a time delay system and a monster McIntosh audio system. My brother who’s no slouch in the piano played Brubeck‘s piano through the time delay system with Joshua Light Show hooked up. Trippy, dude!

Thank you everyone.  This information has saved a lot of angst and most likely a lot of money chasing after something that wasn't necessarily supposed to be present with all recordings.   You read so much about the speakers disappearing and the depth of the sound stage, which I do get on many tracks, but was very curious about Take Five as it's such a famous audiophile song.  I thought I may have something lacking when the specific instruments were clearly coming from one speaker or the other.     I listened to it again last night and was really able to enjoy it knowing that was the intended sound.  

@lowrider57 said:

Listen to a well recorded symphony if you want to experience good imaging and soundstage. There is width and depth with each section of instruments placed correctly on the stage.

This is a great suggestion. Nordic 2L recordings are really well-done.
Also, if you have streaming music, try a movement from a symphony -- Mahler is a good choice -- and then listen to about 1 or 2 minutes of one recording than then go to another one. Quality and approach to symphony recordings vary and one can really hear differences in the soundstage while keeping the musical content stable.

From your description, it seems like you are getting good stereo imaging.  Certainly, your Vandersteens are capable of delivering good imaging. The subject of what constitutes good imaging and how to achieve it is quite complicated.  Almost all types of speakers can deliver great imaging, so it primarily comes down to speaker placement, the placement of the listener, and room acoustics. 

Speaker placement is very important, and the only way to optimize placement is by trial and error.  If you think you have decent imaging already, make tiny adjustments in speaker placement, and on toe-in, and even how much the speaker leans (rake).  Generally speaking, if you don't think the center image seems tight and prominent enough, you should try increasing toe-in so that the speaker is pointed more directly at you.  The tradeoff is that the sense of image width or envelopment of the listener decreases with more toe-in, so you are juggling compromises.  The rake angle will determine how high central images seem to be; generally speaking, the more the speaker tilts back, the higher the image seems to be.  Moving speakers further out into the room from the wall in front of you will tend to increase a sense of depth, and moving speakers away from side walls will tend to make the sound seem to float more freely away from the speakers.  But, sometimes, interference from a nearby wall can artificially create a sense of a wider soundstage, and you might actually like that; again experimentation is in order.

I try to avoid having a large flat surface, like a coffee table, between my listening position and the speaker; if that can't be avoided, have enough stuff on the table to break up the reflections off the surface into something more random.

I agree that imaging on some classical orchestral recordings can be quite impressive.  I like recorded music for that aspect of performance.  But, arguably, it is not that realistic because you almost never get the kind of precise instrument placements one has on recordings when hearing the music live.  If you close your eyes at a orchestral performance, you really don't hear as precise an image; you use your eyes to get the placement.  I don't care that much that most recordings are, in that sense, unrealistic, because I like what I hear.