Your decision to buy a dog is appreciated. But, there should be someone available at home all the time to keep an eye on them. The more you leave them alone, the more they get frustrated & destructive. Any dog if left alone is likely to eat up furnitures, clothes, mats, plastic material - basically, anything that they get off hand. You must be there to feed them atleast. Moreover, puppies need to be fed a litle more than a grown up dog. Once fed, they must be potty trained to make life simpler & easier in the long run. Plus, they need regular exercise. As a puppy, exercise is not needed for upto 3-4 months, but after that daily walks, play time etc is needed to drain off excess energy. Else they develop so much energy that it will be difficult to control/train them.
Adopting a dog is a definite commitment - say for minimum 10-15 years(depends on the breed and health conditions etc).
Regarding the other question - about the breed - Lab & Alsation - these both need very good amount of exercise, else they will turn out to be destructive and arrogant. Both these breeds love to be around their owners all the time. They are very protective too - having said that I am myself a mother to a black lab :)
Think about all this - if you have the time and resource to spend time with your dogs - it will be the best thing to do in life!!!