There are certain items that seem almost sinful to buy for yourself--the marvelous dancing slippers; the dashing belt; the special nightgown. Things you don't need but would love to own.

Now comes that one time of year when you have returned your Christmas gifts, and you have a handful of credits, which somehow makes it all right to treat yourself to a little bit of luxury. If you feel that way, here are some suggestions:

* Men's black velvet evening slippers with embroidered gold fox head, bottom left, made in England for Brooks Brothers, $95.

* Twisted silver-metal buckle belt by Calderon comes with a black leather rope, bottom right; other color leather and silk ropes are available. From Saks Fifth Avenue, $85. (Additional ropes, $25 each.)

* Dotted panty hose, top left, with dash by Evan Picone, at Bloomingdale's and Saks, $6.50. High heel spectator pumps by Allure from Woodies, $98.

* Deluxe cotton terry "relax" robe by Pratesi, top right, with quilted tuxedo collar. Unisex sizing in navy, red, white, light blue or beige. From Jane Wilner Ltd., $150.

* Above, Christian Dior's white nightgown of nylon, acetate and polyester with embroidered bib. From Garfinckel's, $98. --Nina Hyde