Macos – See all information about all processes, daemons, etc. running on Mac OS X

I like to view information about all processes (including every daemon etc etc) that are running on Mac OS X.

I use:

sudo ps -A

Update: I also tried Activity Monitor as suggested by Alex.

My questions:

• Is there a better way?

• How do I identify which of processes are native (shipped with the OS), belong to my installed applications (I.e. Thunderbird, Parallels Desktop etc) or cannot be classified?

• How do I find out which processes sending information into the Internet or local network?

Background:
The system responds slowly and the Terminal tends to hang up after I start the Terminal application for the first time after start up. I tried to remove unused applications, run all of Maintenance.app's maintenance scripts, disabled startup items, disabled all eye candy, bought max. RAM – but still everything is slow.