The third picture is definitely Parthenocissus quinquefolia (Virginia Creeper). As to whether or not it is friend or foe, I guess that is up to you. My grandmother's house was covered in them and she hated them and killed them off. On the other hand, we planted them at our house to try and get them to cover it. As long as you keep them going up and not out there should be no problem, unless of course you want them to spread over the ground. They are a nice thick vine with great fall color (although not much to them in the winter) and after a while they will begin to produce blue berries that the birds absolutely love.
Aside from the main plant in the first photo, in the lower right corner the variegated plant is Aegopodium http://davesgarden.com/guides/pf/go/546/ . It is almost impossible to get rid of once established. On the left side of the photo you may have Pokeweed seedlings. These too are not much fun, but not as horrific as the Aegopodium. Can't quite place the main plant in the photo.
Thank you all for the info! The one on the far left was quite a mystery. I thought the middle was a creeper. It is coming up all over, but not vining yet. These are all in a little woodland garden under a huge oak.