I try to make milestone coasters interesting rides, as opposed to kiddy coasters. I also attempt, if possible, to make them occur outside the US.
I have no clue what my first coaster was, but it was likely either the Jr. Cannonball at Canobie Lake or the long gone kiddy coaster at the long gone Benson's Animal Farm.
I didn't know people even counted coasters for a LONG time, so I have no clue what my number 100 or 200 were.
By the time I started counting seriously, I was somewhere around 175-225, but I didn't hear the idea of milestone coasters until I'd already passed 300.
So, here's what I DO know:
#400 - White Cyclone, Nagashima SpaLand.
#500 - Dreamcatcher, Bobbejaanland (This was supposed to be Typhoon, but I messed up!)
#600 - Zaturn, Space World
#700 - SpongeBob Squarepants Rock Bottom Plunge, Nickelodeon Universe.
#800 - Behemoth, Canada's Wonderland
I have absolutely no clue what's in store for #900 right now.