What would be the proper monetary wedding gift as a member of the wedding party?

I have seen between $50 and $100 given to the bride from a member of the wedding party. :)

Generally at Italian weddings (that my family ahs been to) it is sort of expected to cover your dinner at the reception x 2

Basically if it's a nice sit down dinner let's say it costs 50 a person then your sort of expected to give 100 (or 200 if your going as a couple). But that's just my experience at weddings for family and friends.

As part of the wedding party, you're already spending a lot of money, so it should be whatever you are comfortable with. (Usually between $50 - $100.)

Some of my party didn't give us any gift at all. To a shower, you are expected to give a gift, but "strict etiquette" says a wedding gift is optional.

I give around $100 a person normally.

Yes, about $100.00 should be fine. And one thing about money as a gift is :
Everyone wants it,
Everyone needs it,
Everyone likes it,
No one will return it,
And everyone will use it!!

I do $100 if there are two of us attending, and when I've attended weddings alone, I give $50. There are situations where I've given less such as when a relative married, I was a bridesmaid, paid a three hundred for the dress, shoes and accessories, had to fly, had to pay a hotel and sent gifts to the wedding showers. I bought a crystal vase on clearance for the wedding gift because it was all I could afford!

So, consider what you can afford, and balance that with a guideline of $50 per meal.