That all sounds very familiar, good choices.
You can solder a little 1/4w resistor and LED to the heatbed instead of the surface mounts
that will let you know when power is on.
You can get the heatbed a little cheaper elsewhere but it's a push when you factor shipping costs.
Make sure you get the double connector for the z on the RAMPS and don't forget
the SDRamps if you want to run from a MicroSD card.
SDRAMPS assembled - LulzBot