I have just installed Archlinux & openbox but i have to say i am a bit dissapointed that the applications have this dull greyish (win 95) look: On the picture there are two programs open which are gedit and gcalc which they both use GTK themes. I fixed those to look better by installing lxappearance and setting Adwaita theme. The calculator now looks way better while gedit doesn't:I mean they both use GTK themes. Why don't both look better? Then there is another side to this topic. I am using Kile and this one uses QT theme. How can i make it look like a real QT application - like the ones on KDE desktop? If this is impossible how can i at least make it look like a GTK app? It looks dull atm:EDIT 1After applying the solution my Archlinux with openbox desktop manager looks like this: EDIT 2The only problem I've had with the look of applications from this point on was with the propietary software like VLC and Eagle. Look of the first one can be corrected  by opening VLC and in /tools/perefferences/interface choosing GTK+. I haven't found the solution for the later one yet... 
Archlinux & openbox - greyish win 95 applications
openbox;gtk;qt;gtk3;gtk2
One application is using GTK2 and the other is using GTK3 (unless I'm mistaken). Thus, you need to switch to a theme with both GTK2 and GTK3 components. One theme that supports both is Phenix, but if you search you can find many others. Most GTK3 themes on OpenDesktop.org also support GTK2.As for Qt, install qtconfig (I'm sure Arch has some version of it available) and use that program to set the appearance of Qt applications. It provides an option to emulate the current GTK+ theme, which will allow maximum uniformity, and also an option for the default KDE theme.