You have the choice of SCBCD,SCDJWS,SCEA exams from Sun and numerous other exams from other Vendors.
What will be good for you is something you will know better, based on your experience and where you want to go. (OR) if you are clueless (like me), just take one after the other (there is no particular order once you have cleared
SCJP).
Thinking about the future is good. But if it were me, I will first pass what is at hand (in your case SCWCD), before worrying too much about other exams. Good luck with your SCWCD.