There are a lot of CPU and Memory meters out there, both for text mode like top or htop and for graphics mode, today I will show you two for graphics mode.
Let's start with CPU
wmcpuload
To install this on Debian or Ubuntu run:
apt-get install wmcpuload
once installed run it with:
wmcpuload -bl -wp &
wmmemmon
To install this on Debian or Ubuntu run:
apt-get install wmmemmon
once installed run it with:
wmmemmon -bl -wp &
And here is how they look, once running.

You can run
man wmmemmon
and
man wmcpuload