Partition schema used for Linux installation

I like to use Linux in virtual environment, and I use the following schema for the filesystem (harddisk with 20GB enough to install Nagios for example) :

• /boot 50Mo hda1 ext2
• / 1Go hda5 ext3
• /home 5Go hda2 ext3
• /usr 8Go hda7 ext3
• /opt 1Go hda8 ext3
• /var 2Go hda9 ext3
• swap 512 Mo