That's a tough one...I think you will be happy with either. Speak to your dealer, see if they have both available unless you are pre-ordering for the new 05 plate.
I decided on the silver as I was not sure how the contrasting mirrors would look on the platinum grey. The pic on above on the platinum does look good though...
Go with your gut feel - I do not think you will be disappointed with either.
I do not know if you have sorted pricing but I will be happy to share with you the deal I got (although I do not know whether I should show this on the forum being a newbie (any advice)? If not, I will happily email details and dealer etc
Matt