Identify the sizes you want and then buy those ones from good companies. Look for something which is made of Vanadium or Molybdenum steel(many of the good ones will be usually made of these though). Also if you do get a Torx wrench set,get one which has an additional ball end as this is quite useful if you need to unscrew things at an angle.
You don't need dozens of screwdrivers. A couple of shorter ones and a few ones with very long shafts will be useful. The latter are useful for screwing in motherboards and some of the drive bays which are not screwless.