So I really thought after more than a Install script bash
An example:
cat > /etc/apt/sources.list << "EOF"
deb
http://ftp2.de.debian.org/debian etch main contrib non-free
deb-src
http://ftp2.de.debian.org/debian etch main contrib non-free
deb
http://ftp2.de.debian.org/debian-security etch/updates main contrib non-free
EOF
alias inst='aptitude install $@'
inst apache2 apache2-mpm-worker apache2.2-common apache2-utils bind9 bzip2 courier-authdaemon courier-base courier-imap courier-maildrop courier-pop diff dnsutils gcc postgrey gzip iptables libapache2-mod-fastcgi libberkeleydb-perl libc6-dev libcrypt-blowfish-perl libcrypt-cbc-perl libcrypt-passwdmd5-perl libdate-calc-perl libdate-manip-perl libdbd-mysql-perl libdbi-perl libio-stringy-perl libmail-sendmail-perl libmailtools-perl libmcrypt4 libmd5-perl libmime-perl libnet-dns-perl libnet-netmask-perl libnet-perl libnet-smtp-server-perl libperl5.8 libsasl2 libsasl2-modules libsnmp-session-perl libterm-readkey-perl libterm-readpassword-perl libtimedate-perl libmysqlclient15off make mysql-client mysql-common mysql-server original-awk patch perl perl-base perl-modules php4 php4-cgi php4-gd php4-mcrypt php4-mysql php4-pear php5-cgi php5-gd php5-imap php5-mcrypt php5-mhash php5-mysql postfix postfix-tls postgrey procmail proftpd-mysql rkhunter sasl2-bin ssh tar wget