Stewmac also sell a handy screw driver set for around $40, includes all the guitar screw driver, allan key, etc. bits you will ever need plus bits to 'pre-drill' the position of the screw. i find this tool so invaluable that I bought a second set. originally a DB recommendation too!

I think that it is important to understand that when using screws that forcing a screw into wood creates friction and the metal screws heat up to high temperatures very quickly making the screw susceptible to snapping as it did in this case. Rule of thumb is to measure the diameter of the screw and use a (drill) bit that is 2/3rd's of the screws diameter to bore your hole. It is also prudent to rub a little candle wax over the screw before inserting it into the wood to reduce friction.