sadly your best two rooms are very low ceilings, but given the flexibility of an unfinished basement I would chose that over the others. As Warren suggests, you could treat the low ceiling to reduce it's effects.
If you want some help I have a couple of Everest books on designing a listening room. I could give you some preferred dimensions based on acoustics.
jd
If you want some help I have a couple of Everest books on designing a listening room. I could give you some preferred dimensions based on acoustics.
jd