You couldn't delete much.
Currently WP ships with 2010 and 2011 themes - you could delete 2010 (the current default theme is never to be deleted, it's needed for troubleshooting and often used to get you back into your site)
As of WP 3.5 (soon to be released) it will ship with 2012 and 2011 themes (and maybe 2010?) - with that release, you could deleted 2011, but not 2012 (2012 will be the new default)
You could delete any plugins that ship with WP (Akismet and Hello Dolly)
That's about it. You don't need any plugins for WP to run. You do need at least one theme, the default theme. If you want to use a theme other than the default, you need to have your chosen theme plus the default theme.
So you really can't cut out many files. All the other files are required.
Beyond that, each time you update WP (and you need to, each update contains bug and security fixes), all the files will be replaced.
So really, the best bet is to run localhost to test