htop is a good "replacement" for top, I tend to have a Konsole running with htop a lot. In fact, I have a remote ssh Konsole running to the "other" system we have in our "local" network, and I keep a htop running on that one as well.

ps auxw is nice for a quick "snap shot" of what is running at the moment when you run the command.

ksysguard is like the MS "system monitor", not sure if it is still in newer versions of Windows, but, it was available in Win95 and Win98.

htop, ksysguard, and ps auxw are all very customizable, look at the man pages for them, that is for "ps" and for "htop", as for "ksysguard", I think it has "help" within the program interface.

Hope this has added some information,
Ms. Cuddles