If you want to list all the data and log files plus their sizes try the following SQL:
USE master ;
GO
SELECT db.dbid AS 'DB ID',
db.name AS 'Database Name',
af.name AS 'Logical Name',
af.[size] as 'File Size (in 8-kilobyte (KB) pages)',
(((CAST(af.[size] AS DECIMAL(18, 4)) * 8192) / 1024) / 1024) AS 'File Size (MB)',
((((CAST(af.[size] AS DECIMAL(18, 4)) * 8192) / 1024) / 1024)
/ 1024 ) AS 'File Size (GB)',
af.filename AS 'Physical Name'
FROM sys.sysdatabases db
INNER JOIN sys.sysaltfiles af ON db.dbid = af.dbid
WHERE [fileid] IN (1, 2);