I am often asked by people ‘I have passed my CCNA..what should I study for next?’
My first bit of advice is to celebrate! If you have passed it means you have achieved something great so go and treat yourself and your family if you neglected them whilst studying.
Next – it depends upon what you want. I do think that the foundation exams for security, voice and wireless are a good idea but there is no way that you are ready for consulting after passing them.
If your current job requires those skills then go for them. If you have designs on being a Cisco contractor on consultant then I strongly recommend the CCNP because you will need a very strong foundation in routing and switching technologies. The CCNP also includes voice and security.
I also strongly recommend going for jobs or contracts as soon as you pass your CCNA. Don’t put off doing that for six months while you study for your CCNP.
I hope this helps. I am not your life coach so you must make the choices which are right for you. This is just my general advice.