I get this asked a lot and it is posted on the forum every few days. Here is what I think.
You have to work out what you want to be doing and when and your current requirements. Some of you are working somewhere where they are about to deploy a lot of voice equipment so voice would be the logical path.
Others are trying to get into contracting. I personally recommend the CCNP first if that is the case because you will end up with a very strong foundation plus the CCNP covers some voice and security stuff.
If you feel passionate about something then do that. I see too many people worrying about what others will be looking for. If you love voice then go for that and then look for places who want voice knowledge.
If you want to progress as a Cisco engineer then I think you will need the CCNA – CCNP plus the CCNA voice and security. By this stage I really would expect you to be on a high paying contract or in a more senior networking position.
Let us know how you get on.