Am I running out of RAM here?

"Free memory

This memory is not being used
currently

Wired memory

This information can't be moved to
disk, so it must stay in RAM. The
amount depends on the applications you
are using.

Active memory

This information is currently in RAM
and has recently been used.

Inactive memory

This information has not recently been
used but will remain in RAM until
another application needs more memory
but no free memory is available. If
called upon by a process, this is
quickly changed to Active memory; if
it has been swapped to the hard disk,
it will be moved back to RAM and
marked as Active.

Bottom line: If more memory is required, you still have 'Blue' in reserve.

Source"