I agree with the approach that you spend whatever it takes to get a really good player here, and then get the rest of the pieces cheap, instead of getting all decent players, get one GOOD one. I think backup PG is the least of our worries out of this whole ordeal. Rondo plays a lot of minutes, Eddie/Ray can get away with handling the ball as we saw, and Marbury would be a good fit.
For SF: I think you might be able to get a Grant Hill here, and you might even be able to do it pretty cheaply. He is a smart player, plays hard, and really would like to win a championship. I could see him taking a paycut to come here and play alongside the team we've put together. He has already shown that he is more than willing to check his ego at the door and do whatever it takes. And the best part, he can do it (score, rebound, defend, play multiple positions).
As for a F: Obviously some names are going around that may or may not even be open to the idea. The one name I have been cringing hearing, however, is Antonio McDyess. I don't see this guy helping the Celtics. If we were a young team looking to ad a vet to solidfiy the front court down the stretch, I would be thrilled about this. Excpet, WE AREN'T! We already have veterans to run the team and control the young guys IN THE STARTING LINEUP. Also, when you think about McDyess, you think rebounding is average, defense is average (and that might be generous from what we saw last season, and at this age), offense overall is a little above average. His only REAL asset is that short corner/elbow jumper. While a decent asset, KG, BBD, and even Miki Moore could all hit that shot. I think there is much better talent out there for simliar (maybe even less) money.
Examples:
Rasheed would be my first pick, but the money and mentality would have to fit, that's a wildcard.
My second pick is Gortat. Played great defense against the Celtics, and his athletisism lets him compete on both ends. Also plays hard and has been looking to prove that he deserves minutes he didn't get behind Howard.
Anderson could also be a money issue, but the shot blocking and athletisism alone are reason enough to get him in green (which is good, because that's all he brings).