I wonder if I am getting to be that old guy but I tend to go back to styles that mimics windows XP classic style (not the blue, silver or green one) the most. To me it's the most readable graphics. Right now I am using KDE with the default breeze theme.
I recently used a recent copy of photoshop and premiere and the black UI and the widgets being different from the UI of the whole system really bugged me off (I remember a quote related to windows applications "applications shouldn't skin themselves, it's the job of the windows manager/OS"). I think I like it when all the applications on the installed system (or session) are consistent and look and feel the same.
Though on Linux I remember that Firefox, Openoffice and other big name applications always had a look that somehow was slightly off with the default look of the underlying window manager.
edit: although my first personal computer as a kid was an 8088 Windows 3.1 is the first GUI I used for a long time all the way to XP (then I fully switched to linux, around 2005 or something).