Which Lens to Rent?

Hi,
I have a D50, 50mm/1.8 and 17-55/2.8. Both Nikons.

I am planning to attend a wedding. I am not the photographer, but just a passive shooter, clicking the well dressed family and cousins. Thats it.

Do you think I have the right gear, or should I rent the 85/1.4 or maybe 70-200/2.8 VRII? If you suggest either one of these, I plan to drop ones that I own for the trip.

Another reason to rent is also to try these out for the function for future buy. However, if you think what I own should do the job, I am fine with it.

Thanks.