Agreed. It depends on what you are looking for. You can add subs if you're simply looking for more low end. And if you plan it right, you can always leave the door open to upgrade the speakers later with additional amps if you're wanting more volume, better sound quality, etc, and you can retain the subs you add now. The speakers open up a whole new can of worms. Again, it depends on what you're after...doing just subs is a radically different project than all new speakers + sub.
Personally, i like my new speakers over the stock. It can be a really big and expensive undertaking.