Well I might be a little (a lot) biased but I would suggest following the Cisco route - start with a CCNA, which gives you basic switching/routing. Then you need to choose whether you want to go down the tech route or design route. Tech quals (CCNP onwards to CCIE) are good but right now the market is flooded with textbook junkies who actually know very little, so experience is essential. Design (CCDA onwards) is nice (not my bag) but it can be kinda boring (IMO).
After that you can consider a specialization - security, advanced switching/routing, IP Telephony (thats me) etc etc.
One thing I will say is don't expect to earn vast amounts of money - 10 years ago you may have been able to command a much larger salary with a bunch of qualifications, but I've seen jobs recently requesting CCIE (very high) qualifications offering the equivalent of £40k. Years ago that would have been approaching £100k
Experience is everything. I don't have a qualification to my name, but I am in a very niche market where there are very few engineers worldwide. While that is a good thing, it also means I am limited to where I can go in the future...
Good luck with whatever you choose!
