PPC vs. CPM Ads – 800,000+ PVs & 250,000+ uniques / month

Just curious for some expert opinions in online advertising.
This is in relation to a client’s site that doesn’t seem to be monetizing very well. While not directly related to the project I’ll be dealing with, we were both a bit curious about something.
For a site with the stats listed in the title, would it generally be better to go with CPM advertising (what we were thinking) or sticking with CPC? If switching to CPM, what are the better ad services that you’d suggest they look into?
I can’t give much in the way of details, but it’s a women-oriented site – relationships, and not things like cooking, housework, etc. (so not like something targeted to webmasters that would be more ad-blind).
Any general thoughts?
Thanks.
Jenn

Original post by jhmattern