I usually use htop and tail -f syslog.
I am running ubuntu/nginx/memchache/php5-fcgi/varnish
As it currently stands, this question is not a good fit for our Q&A format. We expect answers to be supported by facts, references, or expertise, but this question will likely solicit debate, arguments, polling, or extended discussion. If you feel that this question can be improved and possibly reopened, visit the help center for guidance.If this question can be reworded to fit the rules in the help center, please edit the question.
I would recommend trying each and every type of monitoring program out there. Use Google and you will find all the popular ones and as you mess with them you will know what you want and what to search for.
Make notes of how it works for you. Everyone has their own style so playing around with different systems is the only good way to find out what works for you.