as I see it, you have to make your personal altar how you feel it should be, not as others think. If its a altar for many people you try to set it in a way that will bring others into the same mind set.
My alter, again as other's have stated, is very personal to me with different items that relate to my heritage, my loved one's who have passed over and for the future.
Although, I will admit that we have several altars throughout our home. My primary personal altar I have in my 'Broomcloset'; another in our bedroom filled with many meaningful crystals and other items relating to our personal present lives and relationship; one in our kitchen that we use on a daily basis with differnt crystals, tools, and items we like to bring forth more postive energy for not only ourselves, but other's too; with much prosperity, good health and protection that we honor every day before heading out the door.
Our home and land is very sacred to us so having altars to share with other's within our livingroom (sometimes moved to the dinningroom) is also seen with many different objects for the different Sabbats; or for what our ritual will require or for personal use should someone be in need of assistance).
I do agree, having what 'feels right' is definately the way to be and as we all like to keep adding to and/or improving our altar's we eventually find what calls to us during our search for what we're looking for.