It's hard to see players go, but the main goal is the present and future of the Celtics.
1. Shaq has played very well with the Big 4. He'll be starting when it matters, but he needs to save energy. His "brother" Jermaine will also be giving 10 good minutes in playoff time. When the playoff time begins to fall, he'll still be able to hit the charts

2. The Celtics couldn't afford to extend both Perk and Davis if they wanted to be overpaid. Danny's answer is clear, and this will help in order to resign BBD.
3. Financial flexibility is the main goal for Danny, so he's putting the Celtics in a good scenario for the summer of KG... Green's contract could be ending in 2012, like KG, Ray, and everyone else but Pierce and Rondo.
4. The pick from the Clippers could be in the 10th-15th area in 2012. Danny has done a very good job in the draft, and that pick combined with the Celtics own pick could be a good asset for trades or in the draft.
5. Health. I hope Perk can recover and be healthy and earn his big paycheck in OKC, but who knows? Could Danny offer part of the MLE to Greg Oden next summer? It would be a risky move, but less expensive.
6. The return in the trade, aside from the draft pick, is very good. Jeff Green will be the main scorer from the bench and could end playing a young Posey role, and Krstic is a great scorer. Playing under Doc (alongside KG, of course) could do wonders for their defensive game, could you picture Wafer or Nate defending so bravely?
7. Nate is gone, and I'll miss his defense, although his offense this year wasn't the best. The C's also traded Luke, Semih and Marquis. 5 players gone, and that opens 3 spots and a lot of especulation (I'm trying to read all the ideas being posted in here). I think Marquis will be bought out, and if he's healthy, he might be back in green. For the other two spots, I'd love what's been said about Dalembert signing for the C's. I don't hate Murphy, but Dalembert fits better. Then they would need a 2/3. Rip (one can dream) would be great, but Danny knows better than us
I think is a very well thought move by Danny, it's still sad to see Perk walk, but the Celtics are team-first, and they will do well this year, and in the future