Hi steelfractal,
It really depends on your setup, how much room you have to position your speakers, and intended listening experience. For example I don't have a lot of room on either side of my monitors, or distance from the wall behind the desk and I have a set of Vanatoo T0's intended for Near Field listening while gaming etc. Since I can't place them at head height, and they are already angled up slightly in their default configuration, I just got some medium foam wedges that serve as isolation pads, and help angle them properly to head height. Personally the pads do a great job of isolating the speakers from the desk, however I must note that my speakers are a 2.1 setup, and they have a crossover that sends all the low frequencies to the sub so that helps keep the mids and highs clear and less vibration on the desk.
I think pads/absorbers are a good starting point and cost effective too.