I've played the Myst1-3 with my partner over the last year or two and have just purchased Myst4.
We played 1-3 on her laptop which is a 1.8 Celery stick with an ATi accelerator and 20GB HDD. There isn't even enough space to install the game! it weighs in at12.5GB installation. I thought Yager was big at 4GB. Even on my machine I'm going to have to do some serious bulldozing to get that much space available (also since I've just downloaded HL2 at over 4GB on 56k).
Oh how times changed.
FYI min specs are:
700Mhz PIII or AMD
128MB for Win9X 256 for XP
32MB DX9 compliant videocard
1.4GB free (although the box says 3GB)
weeeeeheeeeeeeeeeeeee (its a very fitting signoff for my spongbob avatar)