If your desk is up against a wall, the best way of keeping your monitors raised off the desk IMO is by standing them on a shelf. I have some triple track shelving, and the bottom shelf is set about 5 inches above the desk. I used toggle bolts for the tracks so everything is super strong. You can put your monitors on the shelf as well. This gives you loads more desk space, and I use the area under the shelf to keep my MIDI keyboard when I'm not using it. It's perfect! I also have my interface and VRM box on the shelf. One thing I cannot stand is a cluttered desk and this completely solved the problem. 
 
I also have a relatively low desk (about 25" high) which allows ample space underneath the shelf, and the monitors are exactly head height. No neck strain at all. I prefer a lower desk anyway. 

SF_Green
Dagnabbit, Jon! You're killing me!
 
 Been holding out with my 24" single because I don't have room to place monitors side-by-side.  My Omnirax Presto 4 just fits the space I have available and the top is only 55".  I acquired a 3M monitor arm a while ago and have been thinking about getting a second monitor and putting it above my first one. 
 
Does anyone one else do this or have tried it?  What do you think?  I use 2 monitors a lot at work on instruments but they are all side-by-side.  I'm a little hesitant to shell out for a second monitor for a configuration that might not work out for me.

I've thought about getting a monitor arm for flexibility.  I record a lot of accomps and putting the sheet music up on a 2nd screen brought down to the level of my keyboard could be handy.  Although for most usage I'd probably have it pulled back in the side-by-side config.