I just tried to get a flawless installation done with the release version of SharePoint Foundation (SPF10), but using the built-in SQL Server I was getting too many errors in the Event Log. I then tried the recently released SQL Express 2008 R2 and had much more luck using that.
After the install and the Wizard had finished I checked the services and was astonished to see that both the SharePoint User Code Host and the SharePoint Foundation Search V4 were Disabled. When I then tried to start the Search service I got the occasional odd error (...cannot be started with Error 6, Handle is invalid). Well, I finally got it started switching the service from the pre-configured "Local Service" account to "Local System". Go figure!