Presently, you can only easily email marketing lists using Send Direct Email feature using Advance find on Account/Related/Marketing Lists. This is nice, but cannot send attachment with it! The only ways to do this now are:

1) Open a new email and add each individual member to it using the lookup window
2) Use a manual workflow
3) Create campaign, then a further campaign activity - but what if your email is not intended to create a direct response?

Solutions to this are:
1) Allow email templates to have an attachment
2) Allow users to click multiple records (such as on the accounts list) or a single record (such as the marketing list itself) and send a standard email to all selected records instead of just a "Direct Email", which uses email templates. Allowing users to select multiple records and attach a related record (conact, activity, etc) as previously suggested would also be a solution to this problem.