A couple of hundred I would guess in total between all the tents I now have (normal steel, stainless steel, rock and deltas).
I usually take enough stainless pegs for the tent, enough deltas for the guys, and my rock pegs just incase. So all being equal I end up taking twice as many as I actually need...lol
12" plastic power pegs held firm where even a Delta let me down (July 2007, Shell Island, 4am, gale force wind, persistent torrential downpour, sandy hilly terrain)
I have SS and plastic delta's, rock pegs, plastic pegs, plain steel pins and ground sheet pegs. I take them all in a carpenters bag - that way I have the best pegs for the different ground conditions I will encounter. In the carpenters bag also go two mallets and two tent peg extractors. When getting to a pitch, if the ground is hard I usually bang in a couple of plain steel pins to check the ground first for stones, as I don't want to damage my plastic deltas.
Plastic Deltas, 9 inch rock pegs, 6 inch rock pegs, "mushroom-shaped plastic groundsheet pegs, longer steel groundsheet pegs, 9 inch plastic power pegs. All that are not wrapped up with the tents are in a big bucket with the mallets (wooden and rubber-headed).
I have taken all with me as you are never 100% sure what your pitch will be like.