You can set a couple of package upgrade options in the designer through the SSIS options page (Tools -> Options...)

These defaults will be used anytime you upgrade a 2005 package through the designer.

See my post about the Upgrade Wizard for more details on these options.

You'll also a couple of other things on this page:

1. You can set the default language to use for script tasks /components
2. The "comfirm" delete option on the left (the typo has since been fixed!)