I was thinking of using this envelope:

With a card stock invitation inside about .5" smaller than over all envelope.
My question is what should I include?
Invitation Envelope
Invitation it self
---
Response Card
Response Envelope
---
Seperate Reception Card
---
My question is the additional envelope neccesary or do you think its tacky to not include an envelope? Same goes for reception card. I could put the reception info on the main invitation itself.
Curious of everyones layout ideas.