Okay lets talk about how IT generally has been run in the past.
IT is often viewed by companies as a kind of immunization. Firms need to put IT in because anyone who does not purchase IT will soon lose their job. Staff people hate new IT systems, IT people hate talking to staff, and year after year the IT and Internet grows without any clear road maps or logical business justifications.
When I got in to IT 20 years ago it was simply taken for granted that most big IT projects would fail. Over the last 10 years there has been a growing demand for ROI, but this has been actualized in my experience via talk rather than reality. SharePoint projects have been finished but generally sit either unused or even used in ways that actually hurt give no benefit over file shares.
There is a joke about why Microsoft offerings can't go after SAP. Any company that uses SAP has someone who purchased SAP, and anyone who purchase SAP can't be very interested in reality, truth or ROI. I know little about SAP but I think the joke admits something wider about the larger marketplace: a failure to see the truth of the sorry state of Enterprise adoption of IT has created a profession that is more of a religion than a science.
As far as I can tell the conditions around serious SharePoint adoption are pretty obvious. You are buying SharePoint not because its cheap or better than any other product. The reason you have SharePoint over another ECM stack is because its Microsoft. Microsoft is more of a government than a company; by using Microsoft you can engage in modern global network economics.
For example I started working in Microsoft in the early 1990s, when the firm made a big successful play for the Information Worker space. Today the reason firms use Office rather than OpenOffice is because they can find staff who know how to use the product and FEEL COMFORTABLE WITH IT.
I think Microsoft has forgotten this basis of their advantage. Office 2007 and Vista both fail to build on the established space of Microsoft as the system everyone knows and DOES NOT HAVE TO THINK ABOUT. Office 2003 and Windows XP establish a standard set of tools like a standard typewriter or accounting ledger. You know you can get staff globally who know how to use it.
In the 1990s there were 2 ways to do an Office roll-out. One was to give your users Office and spend the money training them. The other was to spend tons of money writing VBA appliations to run in the Office tools to carry out all your special "business logic". Today any Enterprise that went down the VBA is stuck with millions or billions of lines of business logic stuck in silos. The better way to go was to use Office out of the box.
Remember that all generalizations are false, including this one. Still radical standards are good starting points for thinking and here is my radical stand on SharePont out of the box!!!!
Its stupid to NOT deploy as an out of the box. Money spent on styling and custom Web Parts is money almost certainly poorly spent. I would go as far to say that SharePoint should only be customized in cases were you have high accessability requirements (AA or AAA) or massive legacy systems that need integration and portal deployment (in which case you should be looking for a SOA broker). In both cases I doubt MOSS is the best PORTAL tool.
Out of the box SharePoint deployments have the following benefits:
1. You can find staff who have SharePoint experience, gain from collective experience. Just as you don't have to train new staff in Windows or Office you won't have to train staff in 4 years to use OTB MOSS. Think about it!!!!
2. You can connect to other firms who use SharePoint without worrying about customizations. We live in the economy of networks, open standards are good but nothing can beat actually standard tools. The ability to connect to other companies IT systems quickly could give great benefits.
3. SharePoint can be very hard to customize.
I think only very mature SharePoint implementations should be at a point where complex WebParts and Workflows are needed. Deploy SharePoint first as an Out of the Box with solid Information Management rules. BPM and SOA should be long term road maps with SharePoint as a part.