I thought about a used S2000. Then I woke up and remembered I wanted another Porsche... not just another "car". While I never test drove one, I do admire their performance potential. What likely impacted my decision was my experience with my 2.0l WRX. NO low end TORQUE. Same holds true for the S2000. I don't want to have to rev to 6K rpm to finally "get going".
I too, had a 911SC. In fact, I sold it to get my Boxster (2000, non-s). I don't miss my SC yet I love the Boxster. Great balance, great sounds, good power and torque.
Why do you "need" a 2005 S vs previous year "S"s?
Best way to decide is to test drive all 3 (986S, 987S and S2000) in conditions you will use the car... in a commute for an hr? Pleasure driving? track driving? Be fair. Pick the one that is right for you