Although a regular rib works perfectly well, I prefer a twisted rib as I feel that it gives a neater finish. It is very easy to do, just one small change:
Instead of knitting into the front of your knit stitches:
You knit into the back:
Here is the result:
Regular Rib Twisted Rib
To some extent, which rib you choose to use is a matter of personal preference. However, there are occasions when a twisted rib is ideal as more elasticity is preferred. A good example of this is the MurisKnits “Flowered Mittens” pattern available in my Ravelry & Etsy stores.