Your machine is, or will be, an heirloom. Pass it down to your children, or if they don't want it to your husband's nieces/nephews that might give their eyeteeth to have their grandmother's machine. If you do decide to sell it, try to sell it to one of them first.
Don't sell it...use it! If you have other machines that do fancy stitching, great! But how much do you actually use that fancy stitching over "just a straight stitch"?