For those of you asking about the 16 endings, this is what the 'official guide' says:
1) Rating below 1,750 pts: Earth is destroyed no matter what
2) Rating is at 1,750 pts: if you chose to destroy the reapers, earth is destroyed
3) Rating at 2,050 pts: if you chose to become a reaper, earth is saved
4) Rating at 2,350 pts:if you chose to destroy the reapers earth is devasted but still there.
5) Rating at 2,650 pts: if you chose to destroy the reapers earth is saved
6) Rating at 2,800 pts; You're able to create Synergy between organics and synthetics, saving earth and the galaxy (by turning them into something other than they are and taking away their freedom to exist as they are??? Isn't this what the galaxy was fighting against??)
7) Rating at 4,000 pts: if you chose to destroy the reapers and saved anderson, Shepherd lives.
8) Rating at 5,000 pts: if you chose to detroy the reapers and did not save anderson, Shepherd lives.
Those 8 'different ending' were all from a playthrough where you save d the collector base. Another 8 'different' endings like this are listed for a playthrough where you destroyed the base.