Check this article from MSDN about logins transfer:
http://support.microsoft.com/default.aspx?scid=kb;en-us;246133
HOW TO: Transfer Logins and Passwords Between Instances of SQL Server
It's up to you to decide if you want to transfer master/model/msdb to the new server. I'd just transfer the logins using the above mentioned procedure, but if you have a lot of scheduled jobs, custom alerts, etc. you might want to transfer all system DBs. If you decide to to do that there is another article on MSDN on how to do it step-by-step (I don't have the link handy).