That's a pretty vague post, KCH. Are you looking for design or layout advice? Plumbing advice? HVAC or lighting advice? Need to cut in new windows?

I think that it is a good idea to put a full bath in the basement, especially if it might double as a guest room or if you are planning a bedroom area. We did that when we did our basement 7 years ago. The contractor helped me figure out the best place for locating the bathroom - I had ideas but needed to make sure it could work as they will need to run plumbing and it is helpful to be somewhat near existing plumbing.