After getting tired of trying to remember "tar xvzf", I wrote a little script for extracting almost any file type via the linux command-line. You can copy and paste this script into a text editor like gedit and save it to "/usr/local/bin" for convenience. I called mine "untar" since it doesn't seem to be taken. Remember to chmod +x <file> so that you can execute it. You may need to sudo apt-get install unrar if you don't already have it. I'm sure you can see how to add other file types from this example.
#!/bin/sh
me=`basename $0`
if [ $# -eq 0 ]; then
echo "usage: $me <files...>"
fi
for file in $@; do
bn=`basename $file`
case $file in
*.tar)
tar xvf $file;;
*.tar.gz|*.tgz|*.tar.Z|*.tar.z)
tar xvzf $file;;
*.tar.bz2)
tar xvjf $file;;
*.zip)
unzip $file;;
*.rar)
unrar x $file;;
*)
echo "$me: $bn: unkown filetype";;
esac
done