Do what works best for you and not some potential mythical future buyer ... unless you plan on selling in 1-2 years, then you should consult a local realtor and ask about local RE trends.

The best tack to take may be to build it as one big room, use it for a year and see if there is a need to divide it and to what degree it should be divided.

I think it’s good to have options. I would want a rec room/family room and another space. Is there a washroom too?

@WestCoast Hopeful, yes, there is a roughed in bathroom that will be finished with a shower.

I would go with B or C, but I agree with chispa that you should do whatever works for you. I did B in my basement. I divided the two sides with a 48" double door (like french doors, but no glass) - solid wood. If the room is going to be used as a home office or bedroom the solid doors are better for sound insulation. If you do this, make sure the HVAC ducting is appropriate, and think about lighting before drywalling the ceiling. I have recessed cans and center fixtures (semi-flush) in both rooms. Even if you don't build a closet, a future owner could always add one in the future if they want one. Don't do it unless you want it for yourself.

I would go with option B but put a closet in it just in case future owners want to convert it into a spare bedroom. You could leave it open with no doors and put a shelving unit inside while you use it as an office.

full finished space with a bar area, a place to have parties and watch movies, sports etc. No full bathroom, just a powder room. You could always create a small alcove and add a comfy sleep sofa for occasional overnight guests

When we moved into our house, I considered putting up a dividing wall in our lower level family room to create 2 rooms. Space is about 26 x 16. Decided not to because the big space seemed so open and we thought it would be a great family room. Ten years later, the reality is that it was never really comfortable or functional. Might have been good as a pool table/ping pong type family room, but for hanging out & watching tv (with fireplace), it always felt awkward and not cozy.

A month ago we rigged a temporary wall diving the space, kind of a trial run, and it's a thousand times better. I feel like we put on an addition.

The family room with very large tv and fireplace is now about 16 x 16, which actually feels just right size-wise. I was concerned it would feel small, but not at all.

The other room (about 10 x 16) has fairly large double window, so stil has egress as bedroom. We are going to build wall and not worry about closets. Will use the room as storage, as we are sorely lacking. Septic would allow for another bedroom, but easier to just make it a "room", and down the road new buyer could add closets if desired. Still need to build final wall, but we are set on plan and wish we did it years ago.

I guess my point is that sometimes that big space seems more appealing than it actually is, and a little division of space can create a more functional situation.

I would go with option c.

@Rachel / @chicagoans that is what I have decided to do. An open family room/living area of about 15 x 30 ft and the other 12 x 15 ft or so as a "bedroom" that can be used as an office. I'll keep the closets, and just have a normal single solid-core door. I think privacy for the office and quiet sleeping would be better than a den/study room with double door where using it as a bedroom is more of a hack. And, thinking about it, I should be able to have a kitchenette / wet bar area so that can also make the floor a potential suite (in-law or whatever) should someone want to. Unfortunately being the basement, not conducive to older people or those with mobility issues, but still beneficial I think.

@krdpm I understand. My parent's house had a similar size space family room (above grade) and only about 2/3 of it got used effectively; the fireplace, tv, sectional sofa were all down towards one end. That's part of the reason for asking the question. Their room had some other issues though as the windows, doors, and large real wood brick fireplace, made placing a TV or other entertainment center in the room awkward. I shouldn't have that issue, though