Macbook Pro diet

I just used Monolingual to recover nearly 4GB of space on my Macbook Pro’s HDD. I am very tempted to try the option that removes the PPC elements as it seems to be quite safe. The application’s FAQ says this;

You can use Monolingual to remove non-Intel architectures for your installed applications (even if some of the applications are PowerPC-only; Monolingual is smart enough not to remove PPC forks if those are the only ones in the universal binary). However, you should not strip the System frameworks if you want to use Rosetta.

I have no idea how much space this could save though. For some reason the main OS X Library directory is huge so I need to find out more ways to regain some space. Got any ideas?