In order of purchase:
1. Texas Instrument expandable desktop (forget name). Proprietary OS, command line.
2. Atari 800XL (same thing as a Commodore 64). Proprietary OS, command line.
3. Atari ST 4BM (like an Amiga). TOS/GEM GUI OS (very Macintosh like).
4. 468 Clone. DOS/Win31, OS/2 Warp, Linux (pre 1.0 kernel), Win95.
5. 586 P90. Win95, OS/2, Linux, NT
6. 686 P400. NT, Win2k, Linux
7. Sony P IV 1.2Ghz, WinME (yuk!), WinXP.
8. Sun Blade 100 (it was cheap and educational)
9. PowerBook G4 550Mhz. Mac OS 10.1.5, Jaguar 10.2 (in love again).
10. PowerMac G4 Dual 1Ghz & Jaguar 10.2 (off spring of love affair).
I've used many other systems. I haven't really enjoyed any of them since the Atari ST. Linux is great and allowed me to tinker to my hearts content but I found that's just about all I was doing, tinkering.
Never would have bought a Mac until Mac OS X came about. Always drooled over NeXT systems. Mac OS X allows you to tinker but it also allows you to get real work done. I am much more productive now , things really do just work.
Right now, I've got iTunes humming way, Mozilla 1.1 for this website, Mail.app, iCal.app, Blender Publisher on the second monitor, A Word outline composing my thoughts, X-Windows connection running under ssh to the Sun box which runs my JBoss app server, Corel Draw displaying some early web graphic designs, Vim with some Java code, Project Builder with a Cocoa ObjC application I am working on, OmniGraffle with a diagram of my Cocoa apps classes, Calculator with some quick calculations on the tape, and even a Windows Remote Desktop window so I can test some webpage renderings.
I haven't rebooted since the Jaguar shipdate, just place my thumb to the Apple flatscreen power indicator and it goes to sleep instantly and wakes just as quick.
I use the PowerBook for travel and hacking while on the couch.
Linux is great, open source/free software is great, but my God, Mac OS X is sweet! It works and works very very well. Sure it's not bug-free , but what is? Looking forward to 10.2.1 to fix a few things but nothing major so far!
Waiting for my Adobe In Design shipment (free rebate with the PowerMacG4). Hopefully, I will be able to generate some decent documentation with it. We'll see.