try out this function

select name from sysdatabases

where name not in ('master','model','msdb','tempdb','pubs','Northwind')

and DATABASEPROPERTYEX(name,'status')='ONLINE'

i got it from Hall of Fame (Rudy Komacsar Senior Database Administrator)

for more information read the following thread

http://www.sqlservercentral.com/Forums/Topic371321-5-1.aspx