Can't decide between ss/wg ss/yg Datejust II watches

[Nikode]

Hey guys,

I decided to pick up a DJ II for my 21st, but can't decide what to go for.
yg/ss
http://www.rolex.com/watches/datejust/m116333-0003.html (the one I'm leaning towards)
http://www.rolex.com/watches/datejust/m116333-0001.html

wg/ss
http://www.rolex.com/watches/datejust/m116334-0007.html
http://www.rolex.com/watches/datejust/m116334-0004.html

If the DJ II came with this face I'd take it in a heartbeat
http://www.rolex.com/watches/datejust/m116233-0220.html

All in all, budget isn't too much of an issue, I love them all but am leaning towards this one.

this will be my first rolex so I'm wondering :

A) Whether to go for white gold or yellow gold.
B) Which of the above you prefer / think I should consider.

Thanks for your help!