An user in the forums (http://forums.gentoo.org/viewtopic.php?p=261721) pointed out that the note in section 11. "Starting from Stage1" about Portage /var/tmp space requiremets can be misleading because some packages need more than "several hundred megabytes of temporary storage" to build correctly (the case was OO.org) and if someone puts /var in a small partition it can lead to trouble. I suggest to put something like "often using several hundred megabytes of temporary storage (but occasionally it needs some gigabytes to build some packages, i.e OpenOffice.org)" in the note.
KDE also requires more than 1 GB of free space, so "several hundred megabytes" is nowhere near what an average user may require.
Although this is a good point, I think that the user will be able to figure this out themselves, and adding this to the install guide could cause more confusion and cruft. e.g. if a user sees that OO is ~100MB to download, they will realize that it may take more space to build, etc...
