There are very few (and minor) things i'd change about that software and apparently its developers thought the same because the biggest change they did after that was to change the program's theme (in general i think when a commercial program has ran out of important stuff to add the next thing they do is to change the program's theme :-P).
Also Delphi 2 and C++ Builder 1. I refer to the IDE there (they're essentially the same IDE except one uses Object Pascal and the other uses C++), not the language (as a language the ideal would be Delphi 7 with some functionality from Free Pascal like dynamic arrays and generics). The only thing i like from later versions is the inclusion of auto-completion, but beyond that (and especially after Delphi 7) there is way more bloat than good.
And MS Paint up until the Vista version. The only thing it needed was a tool to draw arrows. I curse the Win7+ MS Paint every time i want to draw overlapping rectangles or a rectangle and then something else.
Also WinHelp, whatever was the last version was fine. This didn't "fall from grace" as much as it was outright killed. CHM/HtmlHelp is nice (everything else that Microsoft has produced on the help front sucks) but the ability to add CSS and JavaScript on it means that many programs do add CSS and JavaScript (though TBF authoring WinHelp shows that it is a hacky hack of great hackiness, but i'm referring to the overall UX as a user, not author).
And of course WinAmp 2.95, i do not think this needs explanation :-P
Finally i think Visual C++ 6 (with the addon to add tabs) is the best VC++ version - again about the IDE, not the language. Though overall i prefer Borland's C++ (C++ Builder, Borland C++) mainly because the compilers are much faster (and i do not use C++ much to care about any missing features).
On the Linux side the last version of Xpdf to use Motif was the best Xpdf, GNOME2 is the best GNOME and Gtk2 is the best Gtk. Though Gtk itself is lousy, the only reason to use it is for GNOME.
Mac OS X 10.6.8. It was good, and stable, and nothing that has come after has really added value to the product.
For you. Personally to me things like cross device copy-paste, airdrop, notes and reminders integrations are indispensable now. Metal has brought a huge improvement to rendering speed and of course security between now and then is incomparable.
Snow Leopard, iOS 6, Word 6 (or 2003 if we have to take the modern era), all seem easy choices, yet the companies doing it never seem to notice they jumped the shark. Dropbox 10x the size with built in messaging anyone? Thought not. :)