Also, I highly recommend checking out Chartio (www.chartio.com) - since it's pulling everything from the DB, you can track and measure anything imaginable (http://chartio.com/docs/charts/transform/formulas)
My stack is GA for acquisition, Mixpanel for product analytics, and Chartio for the stuff in between. It works well, but there's always room to improve.
most startups i recommend to keep with simple dashboards
1. Channel grouping (modify how referrers are defined)
2. Attribution model (eg, change to first interaction)
3. Referrer override (specify custom URL to be credited with referral)
4. Custom page path (on page that fires event, pass custom URL path to GA instead of actual URL)
5. Referral exclusion (ignore temporary stray into oAuth domain and continue user's same session)
Hope that helps. If you could use a hand in getting this fixed quickly then get in touch (contact info in profile). Same goes for anyone else with tricky Analytics situations!
Imho the core metrics are quantified product assumptions.
Some related to user interaction, later (hopefully) some related to businessmodel assumptions.
Depending on phase the focus tends to shift from retention to growth.
Alistar and Ben made an awesome chart for their Lean Analytics book (recommended) http://i.imgur.com/0VBP68T.png
These slides by me also might help: http://www.slideshare.net/andreasklinger/startup-metrics-a-l...
hth
cheers