1) Fresh install of 5.0 on Linux using Apache and MySQL
2) Added custom drop down field to Leads module
3) Added that custom field to all views
4) Now leads view is messed up - it shows LBL_FULL_NAME and other such labels. The 'quick-add' shows 'Opportunities' instead of leads.
5) Reinstalled and got the same error.

What a waste of time! This is GA, folks. Shouldn't have to deal with this crap for a simple, 'out-of-box' tweak.