How do I make sure every current user can be "assigned to" in all current and future projects

[Alan Baldwin]

Currently we cannot assign an issue to users or only some users appear in the drop down. At this point with less than 10 users we want all current users to be able to be "assigned to" no matter which project.

[Jobin Kuruvilla [Adaptavist]]

It is driven by the Assignable User permission. Make sure the permission schemes have all the users granted that permission either via groups or via individual users.

http://confluence.atlassian.com/display/JIRA/Managing+Project+Permissions

[MatthewC]

Put the Jira-users group against the assignable user permission (see jobin's link above) in every permission scheme you have. It will do what you want but it's not good practice. You should really be using project roles because what may seem like a good idea now may not be so good in a years time. Then put jira-users group into one of your project roles, that way it still works but doesn't lock you into a hard wired permission scheme.