make sure that you inspect/test the unit throughly, yongnuo has a history of bad quality control.
for ttl exposure consistency i suggest the nissin di622.
agree on this, heard a couple of guys having problems with their yongnuo after 2 events lang.
I really stress on getting a good quality speedlight that you can use in CLS when you upgrade eventually.
Camera bodies come and go pero ang lenses and accessories kahit magpalit ka ng body magagamit mo pa rin
so my vote still goes with Di866 and SB-600. If your budget is kinda bitin, tiis ka na lang muna ng konti, ipon mode para makuha mo yung mas ok na model. mas mapapa mahal ka pa kung kuha ka ng "cheap" flashgun ngayon, tapos benta ka rin eventually kasi hindi pwede off cam.