Here are my thoughts on all of it, in one stupidly long post.
On certs in general:
My opinion is that they're great for two things:
1. Filling in some of the knowledge that you don't already have, and
2. Helps pad your resume/get better consideration by hiring managers when applying for jobs.
Getting a cert doesn't mean you're an expert on the topic you got the cert in, and it doesn't even mean you know the topic all that well. It means you took, and passed, a test. Now, the Cisco tests aren't really passable by just memorizing answers (more on that in a bit), but you don't have to know all of the study material completely backwards and forwards either. A cert is a supplement to, and verification of, real-world experience you've gotten thus far. Being a sysadmin, if I were in the position to hire someone, I'd actually pick the guy with 3-4 years of experience and no cert over a guy who's just out of school and has a cert. Real-world experience is where you learn the most, because the stuff you learn in the field is the most applicable to any other job. There's stuff you have to study for on exams that you'll never see in the real world.
That said, the reality is that when you're applying for jobs, technical people aren't the ones looking through the big stack of job applications -- HR people are. When a position opens up in a company, HR is the one that posts the opening, handles gathering applications, and schedules interviews. HR doesn't know jack about what makes a good candidate for a position, unless the people who work in that position's department give them some guidelines. Technology is such a broad and complicated field, though, that even if an IT department told HR what to look for, potentially excellent candidates could get passed over. Certifications allow an IT department to simplify what HR gets told, and have a reasonable assurance that the candidates they interview would be valid choices for the job position. So, if there's a job opening for a help desk person, and IT tells HR "one of the requirements we have is that the candidate holds a CCENT", then that's something that HR can easily classify candidates by.
On studying for a Cisco cert:
Even the lowest-level Cisco cert, the CCENT (Cisco Certified Entry Networking Technician), isn't really something that you can just pick up a book, read, and pass the test. All of Cisco's certs require a basic foundation of computer knowledge, which is something that the study guides and classes don't cover. Knowing the basic parts to a network (what Ethernet cables are, how Windows works, what an IP address is, etc.) is absolutely necessary before you can start studying. Sure, some of the study guides will go over some of that at the beginning, but they do it in such a shallow and quick fashion that it's just a refresher.
There's really two ways you can study for a cert: By taking classes (and supplementing the classes with light reading from a study guide), or by teaching yourself (by reading one or more study guides several times, using flashcards, and taking practice tests. Taking classes is definitely the more expensive approach, but depending on how you learn, it may be the better option. Self-study will only cost you the price of the books, but you'll end up spending just as much time reading them as you would sitting in a classroom.
Ultimately, it boils down to this: If you're only a computer hobbyist now, start learning more about computers work in general and get a job in IT before you start working towards a Cisco cert.
Here's another factor: You're really not going to pass a Cisco exam without having some hands-on time with real Cisco equipment. You can't just read a book and pass a Cisco exam; there are questions in the exam that require you to critically think and chain subjects together to be able to answer them correctly. For a CCENT/CCNA, you'll want a couple of Cisco routers and switches, so you can get used to how the hardware works and how commands get entered and applied. (Remember my thread about the network bukkit? That's what it's for -- holding all of my Cisco gear at home for learning on.) Unless you happen to work for an employer that has spare hardware lying around that you can have/borrow, expect to spend a good $250-300 on eBay for suitable used gear. If you need advice on specific models, let me know.
Which Cisco cert should I get first?
There are two Cisco certs that you can take a test for and get without any prerequisites: The CCENT (Cisco Certified Entry Network Technician) and the CCNA (Cisco Certified Network Associate). The CCENT is one rung below the CCNA, and is Cisco's official entry-level cert. Consider the CCENT as being half of a CCNA.
Now, while the CCENT is Cisco's entry-level cert, a number of people and companies still consider the CCNA as entry-level. Cisco changes the exams and exam topics for its certifications every few years, and years ago, the CCENT didn't exist, so the CCNA actually was the entry-level cert. However, as time has gone on and networking technology has become not only more complex but also more broad in scope, Cisco decided in 2007 when they rewrote the CCNA exam that with everything they wanted to put in the new exam, it was no longer entry-level. That's when they created the CCENT. In 2007, the CCNA exam got significantly harder, but everyone who still considers the CCNA an entry-level cert probably doesn't realize that.
The CCENT/CCNA relationship is this: To get a CCNA, you can take the test one of two ways: You can take one big "composite" test (currently the 640-802), or you can take two separate tests (known as ICND1 and ICND2). If you take and pass the 640-802, you get the CCNA. If you do the two-exam approach, if you take and pass the ICND1, you get your CCENT. After you get the CCENT, if you take and pass the ICND2, you get your CCNA.
So, which one should you get first? It depends on 1) how much knowledge you already have, and 2) how well you take tests. If you know a lot about Cisco networking before you start studying, and are generally good at taking tests that have a wide range of topics, you might as well take the 640-802 and get it over with. If you're brand new to networking, the CCENT would probably be a better cert to shoot for. There's also a little bit of gambling involved: The 640-802 costs $250 each time you take it (and you have to pay that regardless of whether you pass or fail), whereas each of the ICND tests costs $125. Take both ICND tests, and the cost is the same as if you had taken the 640-802. However, if you take and fail the 640-802, it's gonna cost you another $250 to try to pass for a CCNA again. If you had taken ICND1 and failed it, you're only out $125. And if you took and passed ICND1, but failed ICND2, at least you still got your CCENT.
