Congratualations!!!! How exciting for you! With regards to skincare, don't start anything new ,as the hormones coursing round your body might make you react to products. Basically i did the following:-
1. Take a vitamin supplement e.g. pregnacare 2. Looked after my skin from the inside- lots of fruit and veg and lots of water 3. Hot Cloth Cleansing- massage on your normal cleanser and massage off with a damp, hot flannel 4. A nice mosturising shower cream and then a nice oil or body cream. i used Cocoa Butter from the Body Shop. Not religiously, but when I remembered of when my skin felt a bit tight.
I have had 2 children (2 year old and a 3 month old). i never got any stretch marks (though I think alot of it is down to genetics, rather than any routine). My skin used to be incredibly oily, but is now a little drier.