Recently, I was assigned a task to customize the NewForm.aspx and EditForm.aspx for a particular list. The list was part of a site definition generated using SharePoint Solution Generator.
The reason we wanted to customize the page was because we wanted one custom field to be added (drop down list) that would display all the content types in that site.
You can find the sample project and related files over here
Please rename the file from SharePointProject.doc to SharePointProject.zip after downloading it.