My marker of choice is Prismacolor markers and I have a nice collection developing.
I can say plenty of good things about prismacolor markers, but instead I invite you to discover them for yourself.
The bad thing I can say about Prismacolor markers is that they are very Expen$ive!
I bought my set of warm greys for about $50. Same for the primary and secondary set.
I found them at Micheals craft supply store for $75. If you have a 40% off coupon it will cost you about $47........ For 12 markers. That's about $4 per marker. They tend to cost about $5-$8 individually anyhow. Once I had my base collection I add to them as I need.
I love color so I keep adding new ones to my collection. Fun. Fun. Fun.
Here is a sampling of the ones I use from the infamous last pages of my sketchbook (the impromptu test palette)
Warm and Cool.