I'm a little picky when it comes to my tools for knitting, my yarn choices not so much. In the beginning of the year after digging in my supply stash for a stitch marker I came across some handmade stitch markers I got in a swap a few years ago. I had never used them and since my goal is to buy less I decided to use them. So I got them out for the Imzir hat project. After a few frustrating rounds I got so agitated by them I frogged. The metal markers snagged the yarn, twisted around to the back, made a racket on my metal needles, and made it hard for me to tell the start of the round. Truthfully I think they were poorly crafted but it made me realize that when it comes to my knitting I like what I like, and what I like are flexible rubber stich markers.
Flexible stitch markers really are the best choice in my opinion. They are standard sized, come in neutral colors, are pretty inexpensive and the never damage your work. I have been using them for years and I love them. A few good ones are from Clover or Knitpicks. You can also buy O rings from your local hardware or big box in the plumbing section. I buy #41 as the larger size and #6 for the small. They are pretty cheap but you only get black. I have a few remaining Knitpicks in white that I always save for the start of the round.
For double points I use an open crochet marker to mark the start or a jumbo locking stitch markers. These I got from Lion brand and Susan Bates. The rings that open are great for when you forget to add a marker or for frogging back, Boye makes some nice ones. I like the round ones and not the ones shaped like safety pins. They move on the needles easier. The open crochet markers can be used as cable needles or to hold stitches for mittens or small projects.
Ultimately stitch markers are a personal preference some rogue knitters don't even use them and some knitters use whatever they have around like bread ties, pieces of string, or paper clips I've been known to use all of those depending on the circumstances it's kind of like being in mcgyver knitter. Here's a snap of my stitch marker tin I keep in my knitting tool kit.