I played RCT 1,2 and 3 for years, and I recently rediscovered them in my massive collection of CD's... Oh my god I forgot how freaking epic it was when you actually build something awesome.
I remember saving up and buying RCT1 and the Loopy Landscapes pack for Christmas when I was...what, eight years old? Probably the first game I ever purchased with my own money. That was eventful. Still got the CDs, in fact, now I'll have to go dust them off and see if I can't find a widescreen hack.