If you have selected 70-620 as your client exam then you have to do one of the electives
quoted from above:
If you have selected 70-620 as your elective exam, you have to do 70-270 as your client exam
if i select 70-620 as client , and later on i go for upgrade to 2008 does i have to do again 70-620 or what , caz this also include in upgrade , i think 70-620 / 647/649 for Enterprise Admin ,
my advice is to take one of the isa or exchange...(isa 2004 or isa 2006,exchange 2003 or exchange 2007)
now for the server 2008 you need just 649 then 647.