You may ask me, "why should I use ExpressProfiler if there is standard profiler supplied with SQL Server?"
Of course you can buy the inexpensive Developer Edition, but what will you do on environments where only SQLExpress is installed? Will you install The Developer Edition? Of course not. The solution is to download ExpressProfiler, which doesn't need to be installed. Simply copy a single executable and run it! (it also comes with an optional installer.)
Okay. You may say, "I already have the Standard (or even Enterprise) edition of SQL Server. Why do I need ExpresProfiler?"
1. It is small and simple.
2. It is always ready for action (especially when launched from SSMS, which supplies it with your server connection settings)
3. It is fast. I'm not joking. When you are working in a remote session with servers in your datacenter, ExpressProfiler is much faster than the standard profiler due to its far simpler UI.