I would love a big recreation room and a bathroom in the basement. If the laundry is in the basement I would like to see shelving/cupboards, and a folding counter in the laundry room. I would also like some space left for storage. I wouldn't appeciate things like a bar, sauna or bedroom in a basement.

Would like:
A full bathroom
Storage area
Jacks everywhere for tv and internet
More outlets that you think should be there
Wiring for home theater
Windows!
A great laundry area WITH a sink
Ceramic flooring

Don't want at all:
Excessive overhead lighting
A bar
non-drywalled surfaces

This was my list when we remodeled our basement!

Storage, storage, storage. Deep built-in shelves are nice.
A very clear indication that this is a DRY basement. No musty smell, no carpet on floor (unless it's raised) or anything that might be an expensive pain in the tush if things got flooded or the washer sprung a leak etc.
Bathroom is nice if there is only one upstairs, otherwise I wouldn't bother with the expense.
If the upstairs is very formal, I'd make the basement room very casual, where feet on the table are allowed and you can build a life-size leggo sculpture if you wanted to.
Fire escape, either an exit to outside or a window that is large enough to get through. I hate feeling trapped in a basement.
Soundproofing if it's intended to be a play room (toys, music, workout equipment)
Ditto me on the outlets and jacks
Lots of lighting, but not flourescent
Workshop would be nice if there isn't one elsewhere. A wide counter with a pegboard would do.

Rec area, bedroom(office/home gym), bathroom and storage room. Also, I have space for a workshop or any kind of dirty work.
Also, if you live in a cold climate, add some kind of supplemental heat source down there. Your central heating system may not be adequate. I love my gas stove.
You want it to be comfortable in winter.

We are finishing our basement this winter also. We are only finishing 1/2 of the basement the other 1/2 will be for storage, washer and dryer furnace and oil tank and work shop. I don't want a bathroom. 2 full baths in the house for a family of 4 is enough for us to keep clean. We have a refrigerator in the basement now so we are going make a mini kitchen with just enouth room for a sink, microwave, and coffee maker. I am looking into Ikea cabinets for this. We are adding closets/pantry for storage of bulk items from cosco and BJ's. We will be using dry wall , ceramic tile for the floor, recessed lighting (cans) , and a suspended ceiling. I want to be able to get to any wires or pipes if I have to without having to break through drywall. The lights will be able to be turned on or off at the top of the stairs, as well as in the basement. The basement will also be on a separate heating zone to conserve oil during the winter. The room will be one open space and not divided into smaller rooms. This room is goning to be used mostly by my sons who are ages 14 and 11. I don't think that I would put much money into a basement if it's just for resale. I would just stick to the basics of four walls, ceiling, floor, heat and some closet space. The new owner will have their own idea on how to decorate and use the space. Keep it simple.

A blueprint showing ours is linked from "My Page". We have everything we need or want and no regrets of having overlooked anything. Good luck with yours.

More important than what you put in, is the quality of the workmanship.

In my decades of looking at homes as a broker and renovator, the basements that are left "as is" are the ones that are usually preferable. Too many finished basements display an encyclopedia of defects only matched by the dangers they hide. (A guru of "flipping" in our area advocated this cure for damp basement floors: level it with a wood platform and put on a new floor.)

I wouldn't finish the basement for resale only. I think your return on investment will be poor. It is also alot of work. If you do decide to do it anyway, get permits and do it with qaulity workmanship and to modern codes. I agree with "worthy", a cheap DYI basement can sometimes be a liability rather than an asset.

I have been looking at a lot of open houses to get ideas on finishing my basement. I have started to like a very open basement instead of trying to do too much with it (small exercise room, small bedroom, small home theater room, etc). I like the idea of plenty of COAX, ethernet, phone and electric boxes so I have a choice of where I want to put things without a long cord running across the floor.

I don't think I would do it for resale. I would make sure it looks like a clean and dry basement. That way people would see they can finish it. If a buyer (like you) doesn't really need the space they won't pay extra for it. Everybody has different needs. The main problem with doing a generic finished basement is the plumbing. Some people may want nothing, some might like a bar sink, some might want a half bath, some a full bath. You get the idea.
An emergency exit is also an issue with permits.

Like -
basement that does not smell musty
has no signs of water seepage -
clean, dry

If finished
1. Sound proofing - for noise going up & down
2. Well lit and wired -
3. Storage
4. Flooring that can be changed in event of water - since basements are the most likely place for water issues
-safety features
egress, firestopping,

Rec area large enough for a pool table or ping pong table
Enclosed area for tool bench and tool storage
comfortable area for TV watching

These are universal things I see in finished basements. However, I agree with the previous points that you should not finish it for the sake of selling. The best thing to do is make sure its clean dry, and free of smells. We bought our house with an unfinished basement and the previous owners painted the floor to control dust, and thats it. Also, many cities/townships will require that you create a fire escape as part of code. This can be expensive and you may not want to pay that unless YOU really want a finished basement.