Presser feet are not just frivolous accessories for your sewing machine; they can help make tough sewing jobs tremendously easier if you are willing to take a few minutes to swap out your universal foot for one or more of the various different types of sewing machine feet. As far as I am concerned, if a few presser feet are good, more are certainly better!
Universal or zigzag
This all-purpose presser foot is the default for most straight and zigzag stitching, and even many decorative stitches.
Photo via Bernina
Zipper feet allow you to stitch close to the zipper coils, helping to create a neat appearance and allowing proper zipper functioning.
Buttonhole feet come in a variety of styles, but all help to create neat and uniform buttonholes on your garments. Those with a built-in memory allow you to repeat the same size quickly and easily.
This foot allows you to create an almost-invisible hem efficiently using your machine.
The overlock foot will neaten seam edges on knits and wovens on your sewing machine. If you don't own a serger or it is not suitable for your project, this foot is a nice alternative.
Specialty feet that often are purchased separately
Specialty feet vary by manufacturer, so be sure to check what kinds of feet are available for your make and model. Sometimes, "universal" feet that fit a variety of brands can work for your machine. This list is not comprehensive, but gives you a good idea of the range of possibilities when it comes to sewing machine presser feet.
Commonly seen on heirloom sewing projects, the pintuck foot adds a sweet touch to baby garments and fine lingerie. Pintuck feet come in a variety of sizes - 3, 5, 7 and even 9 grooves - to create different size tucks on your fabric using a double needle.
Totally worth the money, and probably my second most-used specialty foot.
Open toe embroidery
Straight stitch foot
I love making shirts, and use the straight stitch foot to better control the fabric when using short stitches on fine cotton fabric. Using this foot and a straight stitch plate, it is impossible to "punch" fabric down under the throat plate of your sewing machine.
I call this my quarter-inch foot, and it is definitely not just for quilters. Great for doll clothes and many small shirt-making seams, too.
The rolled hem foot allows you to turn a fabric under twice and produce a neat and lovely hem. There are several different sizes that can handle delicate as well as heavier weight fabrics.
This foot streamlines producing a felled seam, and some manufacturers produce a variety of finished felled seam widths.
Not exactly a presser foot, more of an accessory, the ruffler makes uniform pleats in a range of sizes quickly and easily. It is essential if you have a household of girly-girls!
Photos via Bernina
Binder attachment + binder foot
Used in combination, these two "feet" make attaching bias binding on quilts or garments a snap.
If your machine came with lots of feet that are still in the original packing, break them out and experiment a little. You might come up with some new uses, or at least find ways to simplify or improve your stitching quality.