Hi
I have recognized a strange phenomenon in dolphins showing of icons. I have installed win 7 icon package. And if I use the +/- slider in dolphin the icons vary i.e. in some settings it really show win 7 icons and in other settings it shows the default
icons. How come ? 
OW
Iconsets are grouped in different sizes - look at /usr/share/icons/win7/ (or whatever the folder it called) - and vary from very small to scalable. Within each group there's also folders categorizing which icons belong where. Not all the categories on each sizes folders have the same contents - some icons are present on on some of the sizes; others are missing. The most complete iconset we have is oxygen.
If you use another theme, there's always a fallback theme.