I picked
Rhapsody because I really do have a soft spot for all the versions of it... but I really tend to use the
Mac OS X Server 1.x (Rhapsody 5.3-5.6) versions the most. I have two systems running Mac OS X Server 1.2 (Rhapsody 5.6) and one running Rhapsody Developer Preview 2 (Rhapsody 5.1).
I think Mac OS X v10.2 would come in second. I have four systems running Mac OS X, two running 10.2 and two running 10.3. I still spend most of my time on my PowerBook running 10.2.
After Rhapsody and Mac OS X comes Mac OS 8.6. I have three systems running 8.6 and another using 8.6 in Blue Box (on one of my Rhapsody systems). I still do a ton of things in 8.6 which supports a majority of the software I own.
This is a list of the apps I still run in Mac OS 8.6 on my PowerBook 3400c:
3DXplorMath
Adobe Acrobat 5.0
Adobe Distiller 5.0
Adobe Dimensions 1.0
Adobe GoLive 5.0
Adobe Illustrator 8.0
Adobe ImageReady 2.0
Adobe LiveMotion 1.0
Adobe PageMaker 6.5 (and Aldus PageMaker 5.0a)
Adobe PageMill 3.0
Adobe Photoshop 5.5 (with Kai's Power Tools)
Adobe Premiere 5.1
Adobe Type Manager Deluxe 4.6
AppleWorks 6.2.8
Apple iTunes 1.0
BBEdit Lite 6.0
ClarisDraw 1.0
Corel PHOTO-PAINT 8 LE
Corel WordPerfect 3.5e
CorelDraw 8 LE
Fetch 3.0.3
FileMaker Pro 5.0
Fractal Design Painter 5.0.3
Kai's PhotoSoap
KaleidoTile
Macromedia Flash 5.0
Mathcad PLUS 6
Mathematica 2.2.2
MathReader 4.2
MetaCreations Bryce 3D
Microsoft Excel 98
Microsoft Internet Explorer 5.1.7
Microsoft Outlook Express 5.0.6
Microsoft PowerPoint 98
Microsoft Word 98 (and Microsoft Word 5.1a)
Mozilla 1.3.1
Netscape 7.0.2
Netscape Communicator 4.8
Nisus Compact 3.4
Nisus Writer 4.1.6
Opera 6.0.3
Softpress Freeway 2.0.3 LE
PiXELS 3D Studio 3.7
QuarkXPress 4.11 (and QuarkXPress 3.32)
QuickTime 6.0.3 (and QuickTime Pro 5)
ResEdit
SimpleText
Sound Studio 2.0.7
SoundEdit 16 2.0.7
SoundEffects 0.9.2
Strata VideoShop 4.0
StrataVision 3D 4.0
Theorist 2.0.1
I do keep a subset of these apps on all my installations of Mac OS 8.6, but seeing as I use this PowerBook for training, I keep pretty much everything I own installed on it so I can have access to that software. I also keep training documentation on most of those apps on that system too.
As I use the system for training, I've been thinking about putting in a larger hard drive and making a dual boot system between Mac OS 8.6 and Rhapsody 5.6 (Blue Box won't work on a PowerPC 603e, so I wouldn't be able to use 8.6 in Rhapsody) so that I could use that system for learning WebObjects. I doubt I would spend much time in Rhapsody on that system though... Rhapsody feels a little cramped on an 800x600 display.