Given your background, interests and areas of expertise, I recommend completing the requirements for the MCSA as a stepping stone to obtaining the MCSE. Once you meet MCSA requirements you'll need only three more exams to obtain your MCSE. By the time you meet the MCSE's core OS and core design exam requirements (70-217 and 70-219 seem like the most common choices, and thus perhaps your best bets), you'll need only one more elective to complete the MCSE.
Microsoft is expected to announce a new security certification in mid-2003. You can probably complete the MCSA before then, and revisit the issue when the new security cert requirements are announced. If your preference is to work security, you could easily switch to the other track at that time.
Good luck with your studies and exams.
This was first published in November 2002