Are there other sites still using SQL Server with codepage 850 or codepage 437 for their sql scripts?
I'm not sure this is an answerable question - yes, there are always sites on the web using wacko codepages for their defaults.

The most obvious problem when dealing with different collations is joining them together (cross-database queries), especially TempDB.  If TempDB has a different collation than your database, you can run into problems just creating a temp table and joining it to your data.

http://www.sqlskills.com/BLOGS/KIMBERLY/post/Changing-Database-Collation-and-dealing-with-TempDB-Objects.aspx