I am going definitely going with the spohisticated emerald!
If it is a "high-quality" emerald cut and a nice sized solitaire...I would pick it hands down. The quality level makes the difference on this.
I just think it is classic elegance and simply beautiful. When you see a gorgeous emerald cut it can really capture you.
I like the halo, but I do think it is a bit played out right now. I also worry about each and every little stone set in that ring. If your friend uses her hands alot with children, housework, in the yard etc. she may stand a chance of really abusing this type of setting. I feel the other one can hold up more if she really uses her hands.
i guess i tend to go for things a bit more unique so i have to totally agree with you. and this is coming from a person that owns a cushion!