After Network+, what comes next depends on what you want to do for a living and what kinds of systems or platforms you want to do it on. Thus, if you want to become a Windows system or network administrator, the MCSA --> MCSE sequence would make sense for your next steps. If instead you wanted to work with databases, you'd have to pick a platform (Microsoft: MCDBA; Oracle: DBO --> DBA --> etc.; MySQL: MySQL Core --> MySQL Professional) and then let the platform guide your cert choices. Ultimately, it all depends and flows from answering the aforementioned questions (what to do? what to do it on?).
This was first published in March 2004