Is there a way to change the default pages used to edit/create/view a Sharepoint list item without using SharePoint designer? Since I've already created the aspx files on the development machine, it seem's a bit silly to have to install SharePoint designer on the customers server just to set a few default pages.
You can upload the files using a power shell script or an .NET console app. You can upload the files using a solution and a feature.
I recommend using STSDev to create solutions and features for any customisations. The extra work in figuring out the complexities in STSDev, features and solutions is worth it in the confidence I have come release time.
If you create a custom list definition, you can define your own create/edit/list pages. Take a look at the schema.xml in an existing list definition feature, such as DocumentLibrary. For each View there's a SetupPage attribute which points to the list page, and there's a Forms section at the end where you define the DisplayForm, EditForm and NewForm. 'pages\form.aspx' and 'pages\viewpage.aspx' refer to the 12\template\pages folder.