Had a theme issue and white death for the first time. Read a sad story of one developer moving away from WP.. sad... Hence I registered to share the WP LOVE!
Anyway, in order to get to the bottom of the problem which was in the function.php of the theme in question I opened the DB using myphpadmin and found two records that referenced the template and stylesheet.
I uploaded the Classic WP theme, change the theme and stylesheet template name to Classic (not default) using FTP and managed to get the site back up. Then I kept debugging with the theme's function.php till I got it up and working.
Yeah the theme was working on my localhost and NO I dont blame WP as this was the first rough experience Ive had with it and it wasnt WP, it was the theme... All good now.. WP ROX!!