DiceBitcoin, you might want to add an option where you can select if you want to pay a fee or not (and set "Pay a fee" as the standard option). I have seen a lot of feeless transactions and they take forever to confirm (and most people don't like that).
we dont set the fee, the bitcoin daemon does. Sometimes is zero, sometimes is 0.0001 and some others 0.0003 or even 0.0005
Problem is some pools use OLD daemon version,that is why it could be postponed abit(in case the fee is zero). The 0.0001 we"charge" doesnt go in our pockets! Its to even out the withdrawal fees.
For instance, this withdrawal had 0.0002 fee(user paid 0.0001 though) -->
https://blockchain.info/tx/8ef7bab3876b0c6fab7bae0f8798ce30cc1082adb7c33f49dff0d4bcde1ca211