Security Basics: Host IPS -vs- Network IPS? Do we need both?

[lister () lihim org]

Some IPS vendors do not offer a Host IPS solution

Is there really a need for Host IPS if you already have Network IPS covering
the same network area?  What about if you already have other solutions on the
host (ie. file integrity)?

The overhead associated with Host IPS is very high (manage agent installs,
kernel module conflicts, etc).  Just curious if Host IDS is worth it if
the same coverage is provided with a Network IDS.