Choosing a power source

I'm about to embark on my first Arduino adventure, and I have no idea what I'm doing. My ultimate goal is to make a drawing robot similar to this one. I'm trying to choose a power source for the Arduino now. I'll be running 2 NEMA 17 steppers, a servo, and maybe some LEDs. I'm looking at a 12V/2A adapter-- is that too many amps? Will I fry the board if I try this?

Stepper motors - how fast do you want them to go - you might want higher supply voltage for stepper drivers - although drawing is probably not v. demanding.

Servos normally need 6V, which is lower. Basic problem is everything wants a different voltage so you may need some DC-DC converters. Certainly one from 12V to 5 or 6V, which can feed servos. Use a separate path to the Arduino power (its on-board regulator or another DC-DC converter), servos shouldn't share supply rail with delicate electronics.

Too much current isn't a problem (except financially). The load determines the current.