There are two main factors to consider when choosing between organic and regular produce, namely pesticide residues and nutrition.  Information appears below.  Freshness and flavor are important, but these depend on more than how the crop is grown and when it is harvested.  I recall reading somewhere that vegetables tend to be higher in trace minerals than fruits.  If correct, this means that organic vegetables tend to be more important for nutritional content than organic fruits.

It is sometimes argued that organic food is more expensive.  This may be true pound for pound, but that is misleading since it does not count health and medical bills:  The nutritional benefits (see below) can lead to better health;  pesticide residues may cause health problems in the long term.

Levels of minerals in regular crops as a percentage of levels in organic crops
(The lower the %, the better organic is for you.)
    ash  boron  manganese   iron  copper  cobalt
  snap beans   40%   15%        2%     5%     5%     0%
  cabbage   60%   15%      15%   21%     0%     0%
  lettuce   30%   15%        1%    2%     5%     0%
  tomatoes   40%   10%        1%    0%     0%     0%
  spinach   40%   15%        1%    1%     0%     0%
High values in cabbage due to low absolute levels of Mn and Fe in organic cabbage.