Please register to participate in our discussions with 2 million other members - it's free and quick! Some forums can only be seen by registered members. After you create your account, you'll be able to customize options and access all our 15,000 new posts/day with fewer ads.
Adding the extra bathroom on the 2nd floor may be worth the extra cost. My wife and I plan to do the same to our house one of these days.
As someone else mentioned, finishing a basement is not that big of a hassle. Our basement was considered finished but the only finishing included painted foundation walls and asbestos tile on the floor.
A second bath would be more useful when you have family over and save you a trip down to the main floor when nature calls. Plus, you could later renovate the first bathroom once you get the second one in.
Finally, when the time comes that you would sell the house, a second bathroom would probably attract more buyers than a finished basement.