Function keys don't work
If your F<num> keys do not work, this is probably because the kernel driver for the keyboard has defaulted to using the media keys and requiring you to use the Fn key to get to the F<num> keys. To change this behaviour, you have to change a driver setting. Do the following as root:
echo 2 > /sys/module/hid/parameters/pb_fnmode
If it tells you that the file doesn't exist, you probably have a newer kernel and will have to do the following instead:
echo 2 > /sys/module/hid_apple/parameters/fnmode
Place whichever command worked for you in /etc/rc.local to make the setting permanent.
< and > have changed place with § and ½
If the < and > are switched with the § and ½ keys, do the following:
setxkbmap -option apple:badmap
Place that in ~/.bash_profile, or if you use KDE:
Go to the "Control Center" -> "Regional & Accessibility" -> "Keyboard Layout" and press the "Xkb Options" tab. Scroll down and check the "apple" and "Swap keycodes of..." checkboxes. Click on "Apply".
If neither of these approaches seem to work, you can add these two lines to your ~/.Xmodmap file:
keycode 49 = less greater less greater bar brokenbar keycode 94 = section degree section degree notsign notsign
if you use an canadian multilingual layout (where the "ù" and the "/" is switch) use this :
keycode 94 = slash backslash slash backslash bar brokenbar keycode 49 = ugrave Ugrave ugrave Ugrave notsign notsign
Then run xmodmap ~/.Xmodmap.
To map the appropriate functions to your "media" keys place the following in ~/.Xmodmap:
keycode 160 = XF86AudioMute keycode 176 = XF86AudioRaiseVolume keycode 174 = XF86AudioLowerVolume keycode 144 = XF86AudioPrev keycode 162 = XF86AudioPlay keycode 153 = XF86AudioNext keycode 101 = XF86MonBrightnessDown keycode 212 = XF86MonBrightnessUp keycode 204 = XF86Eject