I think this article has convinced me that I should learn Perl. Looks bloody useful for shell scripts, indeed ("a better awk" is the phrasing I've heard).
#!/usr/bin/perl
my $field = shift or usage();
$field -= 1 if $field > 0;
while (<>) {
chomp;
my @f = split;
print $f[$field], "\n";
}
sub usage {
print STDERR "$0 fieldnumber\n";
exit 1;
}