I live and swear by Daemon Tools Pro. I am the owner of a 2 user, 2 year license for the program and from my experience, nothing else supports what DT Pro Std does and does it so eloquently. It supports just about any format I can throw at it, is very light on resources, supports shell based mounting and just plain works. No gimmicks, no hacks to work around, just straight out of the box working!
Some people use Alcohol 120 but I did not find it as robust as DT Pro.
Please note, I am not affiliated with DT. I am just an avid user and fan of the software