I have had several over the years and retain many more. The most useful I have found would be the Cisco Certifications due the the market share Cisco has/had? I would say the CCNP level certifications are the most desired by most.
For new folks entering the field, I would suggest Network+ to get a job, if not is not already obtained,then move to Security+ , SCP, and CCNA R&S. All these certification should only take 60 days from opening the book to passing the exam. If you go beyond the 60 day mark you risk loosing the knowledge you gained.
So after the first year you should have the three certifications listed above. The second year gets fun. I would pick a Cisco Professional Track (Routing and Switching, Security, Data Center, etc) depending on your current job or the next job you would like to have. Each of these tests within the Cisco Professional level should take 60-90 days from opening the book to passing the exam. Get GNS3 or Boson Simulator to practice if you do not have access to the resources. During this year, I would also branch off into another vendor certification like Brocade, Juniper, F5, etc. Add some depth to your Education.
Now for the formal piece of Education: A Degree. It is important and also a requirement for some jobs. See if your employer will reimburse you for classes taken and passed while you are working for them. I had a employer pay 95% of the Masters Degree. I was a rough two years but during that time I earned my CCNP, CCSP, and CCDP (2000-2003). After awhile (few months) the information was so easy to taken and understand because I was working during the day on it and going to school at night. I was a sponge.
Education and Certifications can be difficult to obtain, especially for those of us with families and external commitments. I have to give it to those folks that can do both. My highest regardless to you and your families communication and goals.
Not that your Educational Plan (3-4 year) is accomplished you will notice a sizable difference in your salary (50%-200% increase). This may not happen if you stay with the same company but you never know. Those of you that have seen my bio, may notice that I move around a lot. Well that is the life of a government contractor and military spouse.
Just my thoughts and experience.