Their contributions go well beyond the 2008 title.
If KG and "The Truth" have played their final games in green, where would they each fit among the greatest Celtics ever?
We'll start with Garnett. He's spent only 6 years in Boston, but he also changed the entire culture of the franchise. He turned the Celtics into a defensive oriented team all by himself, and was the primary reason for the C's return to elite status among NBA franchises. The impact he's had on teammates also can not be measured; his presence on the floor has gone way beyond just his playing skills. Being the driving force behind a single championship ranks him higher on the list than many other complimentary players who won multiple titles.
All this likely puts Garnett somewhere in the #12-18 range. For example, Frank Ramsey won 7 championships in his 9 year career, but was also never better than the 4th or 5th best player at any given time. The same can be said for Danny Ainge (3) and Dennis Johnson (2)...