Nero Image Drive is good but it has two disadvantages. One, the NRG format is proprietary to Ahead and the other, it only allows one virtual drive in the system. Alcohol, Virtual Cd and many other products let you have multiple virtual drives at a time and also allows you to mount multiple images in various formats (ISO, CUE, etc...).
One upside of Nero Image Drive is that you get it for free with Nero.
Btw, if anyone has used a floppy image drive please let me know.
Stone walls do not a prison make,
Nor iron bars a cage;
Minds innocent and quiet take
That for an hermitage;
If I have freedom in my love,
And in my soul am free,
Angels alone that soar above
Enjoy such liberty. - Richard Lovelace