Actually no, ghosting is not unavoidable with anaglyph 3D. I have seen images that look stunning in 3D with anaglyph, 100% no ghosting. But here's the problem:
With LCDs and with all the colour temperature, gamma, brightness, contrast, tint and saturation settings not every LCD will be equal. Anaglyph is extremely sensitive to off-set colours, actually it's completely intolerant. There is a reason why the COLORVISION Spyder exists. LCDs are very finicky with colour reproduction, so the default settings that come with NVidia's drivers or the iZ3D drivers may look great on one screen but not another.
So just try to manually fine tune the colours either on your LCD or your video cards settings to get a good image match, but remember that with anaglyph you have to sacrifice overall image colour to get the 3D.
Another good thing to remember (that I've noticed through experience) is that with anaglyph the image looks best if nothing comes "out" of the screen. Ghosting I find usually happens with images try to force the illusion of coming past the screen, so if you can set it so that the screen is the closest that images or objects can appear.
Here is an example of an almost perfect anaglyph image:
http://www.equalizergraphics.com/images/anaglyph.png
Which actually reminds me to say that the result can sometimes be just a result in how well the anaglyph was created, not just how well your monitor shows it.
Here are a couple of other decent examples:
http://farm4.static.flickr.com/3071/2568989705_3cd4d569ce.jpg?v=0
http://abdownload.free.fr/Anaglyphs/18/18665_Ellenville_4th_X_anaglyph_b.jpg
http://atomontage.com/sshots/atomontage_tribush_2_anaglyph.jpg
here's an example of a good anaglyph, but the depth is too deep, should be much shallower:
http://members.multiweb.nl/emil/anaglyph.jpg
and here's one that just makes me want to puke:
http://upload.wikimedia.org/wikipedia/commons/a/ac/VisHumanCT-Anaglyph-2.png
anyways, I really hope all that helps.