I'd re-sign Ray Allen and run back the same starting lineup next year. Ray's play just has flat-out not dropped off with age.
You've got Pierce, KG & Rondo under contract anyways - so why not?
The following offseason we'll be able to parlay Sheed/KG into something better than 6th man type guys, and Ray will still be a solid contributor off the bench.
In that scenario, maybe we only win one or two playoff rounds next year and have to wait until the following year to reload for another title push, but that is a scenario that this Celtic fan will take all day long.