ok let's skip the pen to typewriter to computer steps 
486/33 with 4mb ram and 120mb HDD (later upgraded to 8mb ram and 1GB HDD) dos/windows 3.11
1st big jump
PII450 with 384mb ram 16GB HD 8x cdrw running win98 later win2000Pro
2nd jump (less big but a jump in a different way)
B&W G3 300 with 786mb ram 20GB HD 48x cdrw OSX Jaguar (the biggest jump was seeing a mac with the same age as the PC handle the latest OS while the PC was asking for mercy with WinXP on it) when I got my next mac this was my MusicPlayer until I sold it and bought an iPod instead so maybe we can note that too as a jump, from desktopaudio to portable audio ;-)
3d minor jump
TiPowerBook G4 400 1GB ram 20GB HD 52x cdrw LaCie & Airport (first wireless system I owned)
the jump was more in the effect of my PowerBook running faster on Panther then on Jaguar...
4th jump (because someone stole the TiPb one year ago...)
RevA Dual 1.8Ghz G5 with 1,5GB ram 160GB HD, 8x SuperDrive, Airport Extreme
I have some other computers wich aren't listed because they are bought inbetween when they were allready 'old': 486/25 4Mb Laptop, Classic, Performa 5200 (wich a friend uses to play old mac games...) and two Pentium 166MMX (at least one is Intel, think the other is AMD...)
486/33 with 4mb ram and 120mb HDD (later upgraded to 8mb ram and 1GB HDD) dos/windows 3.11
1st big jump
PII450 with 384mb ram 16GB HD 8x cdrw running win98 later win2000Pro
2nd jump (less big but a jump in a different way)
B&W G3 300 with 786mb ram 20GB HD 48x cdrw OSX Jaguar (the biggest jump was seeing a mac with the same age as the PC handle the latest OS while the PC was asking for mercy with WinXP on it) when I got my next mac this was my MusicPlayer until I sold it and bought an iPod instead so maybe we can note that too as a jump, from desktopaudio to portable audio ;-)
3d minor jump
TiPowerBook G4 400 1GB ram 20GB HD 52x cdrw LaCie & Airport (first wireless system I owned)
the jump was more in the effect of my PowerBook running faster on Panther then on Jaguar...
4th jump (because someone stole the TiPb one year ago...)
RevA Dual 1.8Ghz G5 with 1,5GB ram 160GB HD, 8x SuperDrive, Airport Extreme
I have some other computers wich aren't listed because they are bought inbetween when they were allready 'old': 486/25 4Mb Laptop, Classic, Performa 5200 (wich a friend uses to play old mac games...) and two Pentium 166MMX (at least one is Intel, think the other is AMD...)