I have heard people on the forums mention that assists were basically window dressing, similar to heights and weights.  Can anyone explain why this is?  Does this mean that looking at assist to turnover ratios, and similar stats, aren't worth considering?

Assists get determined after a shot is made. They have no impact on scoring. I think :)

Assists are more of an indicator of how much impact a player is having on the offense. This is why guys with high Passing will end up with higher assist numbers.

Assists are worth looking at because an assist is a pass that directly leads to a basket, and baskets are the name of the game. A player who gets many assists can find teammates and help them score an easier bucket (see recent gillispie thread). A/T ratio is the best indicator of PG production. High assists with low turnovers is the name of the game for PG's. An excellent A/T ratio is not window dressing because it measures actual, simulated production (unlike height and weight).