I think it will be a good idea to go with SCWCD exam. certified in web servicess w/o being certified in Servlets doesnt sound so appealing to me.
about the SCBCD test, well, I am myself preparing for SCWCD even though I much more comfortable with EJBs. but with all the new technologies coming for object-relational mapping, I dont want to give $150!! for SCBCD.
Java Developer Test: I dont know why anybody would give this test, unless they have lotsa time on their hands. There are too many Certification Tests out there more marketable than this Java Developer test..
for myself.. i think the web services test will gr8 to give. but u gotta be strong in Servlet n JSP b4 that. and the best way be strong is to give the certification! Even from a job perspective, I think SCWCD will still have more takers than the Web Services certification.
btw : Web Services =