NHibernate Profiler
Recently I had to update our domain model and it required some NHibernate profiling. I have installed trial version of NHibernate Profiler, and it rocked. The fact that it was not only able to show what was going on, but also give suggestions how to improve NHibernate usage just rocked (unlimited records returned).
I also loved straight, cut-the-bullshit communication with Oren, who has responded quickly (to the bug that I found). Worked for me, and we are going to purchase a few licenses.