The 2nd ext4 partition can be
/home. It will contain your users' data such as photos and music, but it will not contain any Linux games. This is because Ubuntu has its own system of placing application or program files in special places within its system. There is no way to install games in `/home' or any other partitions or folders of your choice. See Linux Filesystem Tree Overview for details.
You have three choices for the NTFS partitions:
One, Create two folders under
/media such as
/media/WinData and mount the partitions there.
/media is where the partitions are mounted when you select them in the Nautilus. The advantage of mounting the Windows partitions in
/media is that they remain available on the left panel of Nautilus as drive icons. However, if you don't want the Windows partitions to appear with drive icons in Nautilus, then consider option two below.
Two Create two folders under
/mnt such as
/mnt/WinData and mount the partitions there. If you do this, the partitions won't appear as special icons in Nautilus. Both these options are explained in more details at Mounting Windows Partitions.
Three This is essentially the free for all option. For example, you may create two folders
/ and mount the partitions there.
In terms of functionality in Nautilus, two and three are the same. Two may be preferred for historical reasons and keeping the
/ root less cluttered. In both cases you can create bookmarks in Nautilus to easily access the mount points.
There seems to be a debate about which of this three is right. See Why have both /mnt and /media? for some answers.