Soundstage...How to determine what's right?

Have started upgrading my system and will be trying to optimize the soundstage. A lot of reading has me thinking that I really don't have enough information and experience to get there.
Terms like "congestion, width, depth, and height" have me wondering how much is in the recording and how much is introduced by the system? Are there reference type cd's that people use to determine how their system is progressing? I so, could you help with a list of cuts with info regarding the placement of vocals, instruments and examples that contain material that is not congested?
Thanks for any help.
I have both CD's mentioned by Rodman and they are good ones!

Additionally another good Chesky CD is: The Ultimate Demonstration Disc: "Guide to Critical Listening". It contains some wonderful music. More importantly however, each musical track was chosen for its ability to convey transparency, midrange purity, imaging etc., and each includes a preface track, verbally defining what you should be listening for/hearing....
More to look at. Thanks again. Looks like a person could spend a fortune just for demo disc. Will have to narrow it down to one or two. Any chance of getting thoughts on the best two or is that to personal a decision?
All solid state. Haven't ventured into tubes though have been tempted. Read so much about the sound of tubes. Afraid that if I slip into that I might not find my way back.
Thanks again,
I have the Chesky Ultimate Demonstration Disc as well as the Sheffield disc. I like the Shieffield disc for its 'walk about' cut, and its 'out of phase' cut but other than that it didn't impress me. It does have 'burn in' tracks some might like to use.

I didn't find the Chesky disc all that useful, especially compared to the Opus 3 disc's, which are much more varied and easier to 'understand'. But I did get the Opus 3's first and was thoroughly familar with them when I got the Chesky. And, I've got to admit that perhaps my system just wasn't up to the level where I could appreciate the benefits of the Chesky, a label I have been more disappointed by than impressed. FWIW - YMMV.
The LEDR demo on the Chesky provides a series of pulses that begin by going UP to help you find ceiling reflections that might be alleviated with absorption. Then OVER which starts 2 feet beyond the left speaker and describes an arc over the center stage and beyond the right speaker, then LATERAL from past the right front of the right speaker and ends at the left rear of the left and vice versa. You can find a more in depth discussion of the test in the December 1989 issue of Stereophile. Another track has Dave Chesky describing where on the stage he has placed his microphones, and a variety of locations on this stage from which he is speaking and striking his tamborine, so you can determine whether your system is recreating the info and/or whether you can hear it. Very easy to understand. The disc is available direct from Chesky for about $16.00, and perhaps for less on Amazon. I have often wished I wasn't so familiar with live music(acoustic and amplified). I'd have saved megabucks over the last 30 years. Yes- The pure musicality of tubes is addictive. Unfortunately the best are always the NOS ones from the 40's through the 60's, and BOY are the prices going up!!
( Just to make it a bit easier: here's the URL for that article in Stereophile. They do a much better job of explaining the LEDR test. That disc also contains a left-right imaging test that extends beyond the speakers which a great many systems can't reproduce.