Or you could use a single regular expression -

#!/usr/local/bin/perl -w
use strict;

while (<DATA>) {
    s/(\w+)/\u\L$1/g;
    print "$_";
}
# or just a one liner -
# s/(\w+)/\u\L$1/g, print for <DATA>;

__DATA__
foo bar
ned KelLy
james bond
[download]

And the output is -

Foo Bar
Ned Kelly
James Bond
[download]