Improving imaging

Excellent point, Dougholdco. A cheap, quick check would be to at least pull-out and push-back-on your interconnects at all connecting points, Mmccoy. That will clean the connections enough to get a sense of whether this is a contributing factor in your situation.

I also vote for speakers - but repositioning can also help. I now have mine towed in at about 30 degrees - mine are about 12' apart. I have KEF Reference 3's that I purchased because I liked the soundstage - they didn't have the lowest frequency response but they sound good and are fairly accurate. I have also listened to Meadowlark speakers and liked what I heard - they are also efficient and reasonable in cost.
I believe some tube amps also present a nice soundstage when working with a good speaker. I like the Cary single-ended (SE) amps but tubes do take some tweaking.
Shop with some CD's you like and trial speakers in your own environment if possible - quality dealers usually will work with you on this basis.
Good luck and good listening!

Yes, I have had imaging problems (mainly a center image that was no longer on center) that were/was remedied by simply reinstalling the cables a second time.

I have noticed when upgrading my modest system images became more distant.
Deeper soundstage, laid back sound. When you see these words used to describe many expensive components, it means small image. The further the stage the smaller the image, and you lose image height and layering (on most recordings).
That's why studio recordings sell and "recorded live" usually do not.
However a lot of audiophiles and reviewers seem to prefer that row "Z" listening position for some reason. Maybe it is more accurate.
I have some SACD's (very pleased overall). On one Santana recording, I think it may be the last track, the vocals are barely audible he is so far back. And Tony Bennet Unplugged-recorded space is verly realistic, but it is though I am in really bad seats! Sounds better in my car.

When I first got my speaker placement and room acoustics working right the sound stage was large and individual "voices" were apparent. I thought this was what I was looking for. Over the past two years I've played with a number of areas of my system, please search "winter lessons" that I posted a while back. I outline a number of "tweaks" that have worked for me.
To give a quick overview, assuming the basic system is adequate (you had imaging once) and your speakers are properly placed, I have found power cords, power conditioning, interconnects, footers and shelving can add up to equal at least a new amp. Today my imaging is simply fantastic. I do not need to "look" for the instrument it's simply there. The stage is wide and deep with complete definition through out. Each "voice has space around the sound, even in congested passages. The difference from when I first felt I had it and today is basically the difference from a mid-fi to hi-end system. There is a huge amount you can do to help bring the best out of the system you have. I recommend experimenting with your system, start where the above posts are starting, make sure your equipment is working well and is capable of what your looking for. Then the real work should start, try stuff, ask a local dealer if you can take things home (power cords, conditioners, footers) and experiment. Be sure the products you try are broken in or you'll have no idea what it's effect on your system was. Search "winter lessons", "shelving" and "Nueance". Redkiwi has written some excellent posts on shelving (above) and must be read. Good-luck and enjoy the music! J.D.