We've used MOM with pretty good success since it handles the purging, viewing, and other concerns outside of data entry. The caveat to MOM is that it doesn't do *NIX out of the box(at least the version we have). There are connectors and such. Another option is look into LogLogic. This takes log info from network devices, but has an open web service API that you could tie into. MOM has APIs as well, so you could funnel down to something like LogLogic.
