discovering them and doing some research on them.
I presently use Winsor & Newton Artisan paints. However, once I get through those, I will be switching full time to Holbein Duo Aqua and Royal Talens Cobra because of their handling. But, sometimes you just find the right color and gotta have it regardless of the brand!
I occasionally will use a medium, though presently, my heart is sold out to alla prima painting. (Though, artist and Chair of Painting at the Pennsylvania Academy of Fine Arts, Al Gury points out in Alla Prima: A Contemporary Guide to Traditional Direct Painting that one-sitting paintings are but one facet of working in the alla prima tradition; glazing during and after completed is within it as well.)
I use synthetic brushes—Princeton and Artisan—because they are (relatively) inexpensive and get the job done. Plus, because I use water-soluble paints, I find that synthetics hold up in water better than natural hair brushes.