I mentioned how I assigned buttons in your
Any combat tips please? topic, but can expand on that.
The face buttons being the easiest to control and differentiate in the heat of battle, I reserved for my most frequently used actions. Playing a melee warrior, that meant X became melee attack. The A button falls naturally under the thumb, making it easiest to switch to when using the X button, so I assigned that to ranged attack (a bow being quite useful early to mid game for combat, even without investing in any ranger skills, and at least handy for breaking crates, etc, late in the game). The Y button is the next easiest button to get to from the X button, IMO, so I assigned my most used active skill, Rush Attack (rarely used early in the game, as it is generally better to get opponents coming to you, but very handy later once you start encountering rangers and mages and/or opponents that try to run away). That left the B button for Whirlwind, helpful when surrounded (though with the 1.03 release, weapon swings that go through other opponents in addition to the target do damage to them, so depending on the positioning of opponents, Whirlwind may not be needed).
After getting the creature, I assigned it to the Down D pad direction, as that was the least convenient button to reach, so perfect for something I would rarely need, but wanted handier than having to go through the inventory.
After learning the healing spell, it needed to be ready for quick (if only occasional) use, so I put in on the Up D pad direction, which seemed the most natural mapping after getting used to F1 for potions in a couple PC games.
On the Xbox the left stick controls movement, so after getting the battle tower I assigned the dragon stone to the closest button (Left D pad), as that seemed the most logical association for the action to teleport back and forth to the battle tower, or between platforms in the tower. The dragon morph stone (which allows you to change between human and dragon), then went to the Right button, to be opposite.
On the Xbox, the actions assigned to the A and B buttons can sometimes get triggered when finishing or exiting out of conversations, etc, so it is better not to assign skills with a long cooldown or high mana requirements. I assume if you can go though conversations using the A/B buttons, the same could be the case on the PC.
Before getting the battle tower I had Left assigned to Rush Attack at one point, and Y as Whirlwind, just to avoid using the B button, but had to switch that around once I got the 2 extra actions that needed to get assigned. It wasn't a big deal, though, as this issue is fairly rare (only noticed it a couple times).
) gamepad I ever got (to play a freeware game, no less) had 4 buttons and a D pad. Two of the buttons were 'repeat' functions of the A and B buttons, so holding down the RA/RB buttons were the same as repeatedly mashing the A/B buttons. I have not seen that in any recent gamepads (haven't been looking actively), but it would have come in handy a couple times (that function may be able to be replicated with gamepads that have macro buttons).