With some extra tools (from Darin_dbtools on Matlab file exchange), you can also use conditional breakpoints to do a lot more than stop at a particular value. You can place code in the "conditional" breakpoint to look at SELECTED variables as your code runs (dbdisp), change variables (dbassign), or to call user code (dbcall). And, you can CHANGE any of this within the debugger as you code continues to run!
For example, if you place a conditional breakpoint with the condition: "dbdisp([x,y])", your code will act as though disp([x,y]) has been inserted in front of that line until you disable the breakpoint. Since these routines always return false, the code will not stop.
The combination of break_place.m and break_place_button.m provides a mechanism other than break points to interactively interrupt running code, causing it to drop into the debugger on a mouse click. For example, you can have a days-long loop running unattended, interrupt it by clicking on a button, look at things in the debugger, then continue as though nothing had happened. It isn't 100% solid across Matlab configurations, but has still saved me hundreds of hours of debug time.
Darin_dbtools_demo gives further examples.
Hope that helps.