My first customization was really simple and logical. Being MS CRM 4 a strategic marketing tool I don't get why there isn't a tab called Marketing at the Contact form. Create, Save and Publish! Don't forget to Publish!
The last finding will only affect the order of the values. Check out Preferences attributes (custom) versus Send Marketig Materials (system attribute). To improve the user experience you should present the new attributes respecting the system order (Yes/No). The worst part of this is that you can't change the order (Move up or Move down) once the attribute is created. You need to unpublish it (remove it from the form then publish) and then you can delete it and create it again (create, add to form, publish). Boring! So be carefull!
Microsoft if you're listening please change de default bit attribute order! Well, if I don't shout I will never get it so I guess it's better to shout than not to.