While the plugin which shows big amounts of ore everywhere is a very good way to counter xray, it also backfires on the players who mine legit.
It will look like your walls are full of ore ALL THE TIME, which they are not as soon as you want to mine the first ore. I found this to be very irritating after a while.
I think the plugin which calculates how much ore you would be able to get is less of an intrusion on your daily mining unless you are extremely lucky all the time.
My vote goes to the fair-distribution-of-ore plugin.