I didn’t take much notice of the Winter ’12 Force.com Platform Release Developer Console as there was no mention of that important word “breakpoint”. But if you are in debug hell then the features that are provided to allow debugging without having to add System.debug calls – including the ability to capture and view the heap at points marked in your source code – are worth investigating.
This (hour long) presentation demonstrates how to use the features:
It also suggests that the Eclipse tooling (and 3rd party additions to that tooling) will eventually be able to use the same API. I find the current browser-based console fragile (using Chrome) and a bit awkward to use as it packs a lot of tabs and frames into a small space; hopefully the richer UI facilities in Eclipse will help. But worse, on the sort of pages and code that require debugging, i.e. non-trivial larger ones, the volumes of data that the tooling attempts to move from server to client are so large that the time delays make the tooling barely usable at all.
Note that while this tooling can be used as you develop your managed package, when that managed package is installed in a customer’s org all the code-related debug information is unavailable (by default but can be turned back on via a support request) so the ability to debug is also lost.