Workout Room/BB court/Batting Cage +5
Pool Table +1
I halved mine. 10 mil is nice, but 5 is definitely more than enough for a reward.
The chick is a must. Not only for sex but to have someone else there besides yourself. Social interaction is an extremely important thing and I doubt very seriously I would keep my sanity being alone for 10 years.
Skylight - Being in a basement with no natural light for 10 years? No way.
Garden/Greenhouse - With that and the skylight, it would make it feel less like I was being confined to a basement as I would have things that resembled the outside world.
Hygeine/Tub - That is just a given.
Workout Room/BB court/Batting Cage - This is just a steal for the price taking into account how many activities you get with it.
Library - There had to be something to do in the downtime.
Pool Table - For 1 point?! Who wouldn't love a pool table?
The chick really makes it though as I would have someone to actually do these activities with.