Why good sir, gnomes of course! Playing them is a blast
*ducks*
Now on a more serious note, pretty much anything with a Cha and/or Dex bonus tends to be nice. Charisma tends to be important for the arcane/divine classes that generally make the best blasters (such as sorcerer, shugenja, warmage, etc.), and having bonus spells perday is a must for those intent on using more than a single spell per battle. Dex, in turn, is nice for increasing the likelihood of the various ranged touch blasting spells to hit. You could theoretically get by with just AoE spells (which need Cha more than Dex, unless you are on the receiving end), but this is inadvisable, so a higher Dex helps.
It should be noted that Pathfinder is very friendly to blasters in this regard, with Dwarves being the only race that doesn't have a (potential) bonus to at least one of these, and multiple races have +2 to both Cha and Dex. Unfortunately, unless you are using adapted versions of the aforementioned classes, casters are now fairly balanced between Wis, Int, and Cha, with most of the blasting classes being Int based (I believe), making elves (with a +2 to both Int and Dex, as well as a +2 on CL checks vs. SR) generally a superior choice.
