Backup Compression in SQL 2000 and SQL 2005

Below are the methods available to compress backup in SQL 2000 and SQL 2005. Please comment incase you need more information on this!

Method 1
NTFS Compression available in Windows Servers using NTFS File Format.

Method 2
Using GZip (Best Compressing Software – Open Source Freeware) compress the .bak files.

Method 3
Using Gzip Compress backup on the fly using pipe read/write (Only in SQL 2000)

Method 4
Either add more disk space or buy backup compression software like litespeed, HyperBack.. or use SQL Server 2008 with backup compression technology...

I did a trial compression using above methods and below is the ratio of compression...