Simply because it is not a fixed price, it is always keep changing

Interesting point. On what factors does your pricing change? Usage, users, etc?

Sticker shock for most customers. They don't want to scare off customers who just look at price.

Without having any idea about price how do companies know what solutions are within their price range. As ECM and E2.0 systems start becoming more mainstream and more smaller companies begin to approach adoption, will an unposted price scare them off prior to pursuit? Less of our business in the coming years will be Fortune 500 businesses, how do unposted prices serve that market?

Some vendor's price lists are nearly 100 pages long, and to get certified on pricing their solution, you attend a 5 day training course on it. At my company, we lived in that world, and simplified our pricing down to a single page. My philosophy is that if your pricing can't fit onto the back of a business cad, you have major problems.

In your opinion, are any vendors doing it right? I've fought many battles to get things posted publicly, but can't find examples of other organizations that have done it. Perhaps no one wants to be first.

I think as the market continues to move away from Fortune 500, the vendors that have public pricing are the vendors that will win. If there isn't enough value for your price, it doesn't matter if you post it or not, you still won't win the business. Box.net, knowledgetree, socialtext, PBWorks, 37signals, etc. all post pricing. Note that they're all in the SaaS market. I don't know of any installed commercial platforms that post but I think it's a mistake for the long term.

Just because it ain't McDonald's. Sometimes I wish it were, dealing with licenses is very much different that buying Chicken McNuggets. Granted it would be easier and a lot less confusing. Just ask your favorite vendor for a price list, I'll bet you have to ask more than once and you might get a list of short descriptions or product codes with seat counts.
In my experience it's not something a sales person wants to hear, but recent economic events seem to have loosened the grip.

I'm seeing a lot of vendors gaining ground in terms of market share and posting their pricing, all of the activity seems to be on the SaaS side. I'm thinking that the installed and licensed side will have to play catch up.