Am not a developer, but since I am on the computer all day and night, the dark and light textures are easier on the eyes. Theme installed on my system also contains color changes for words in Java. Since am studying Java in school is a total asset! Operating systems are humongous! Hours and hours are spent on scripts. Things we all take for granted, takes hours of work to make right!. If you are using Gnome, the best thing is to go to
http://www.gnome-look.org . That is where I found the themes I enjoy. Remember there are two pieces that make up the looks on your desktop. You have the GTK theme and the Window theme. Is a little complicated still for me to explain, so am hoping you will head to the above site and check these themes out. This will help in your decision to pick what looks good to you! Personally, took me a good month to find exactly what I loved and worked the best! I had many themes before I settled into the present, which I have used since this past July when I started using Ultimate 3.4. Once you download the theme or theme's you want all you have to do is go into the terminal type sudo nautilus and you password. On the left side of the window that pops up click on file system on the bottom will see usr folder open it, next you will see share folder, open that and then scroll down to themes and open it. From your download folder you unzip your theme and then move the theme into the themes folder that is open. Right click for properties as have to change permissions. Under the Permissions tab you have to make sure Owner and Group are set to root. Under Owner which is set to Root folder access needs to be set to create and delete files. The next 2 permissons for group and others is just set to access files. Once that is all done can close nautilus-window and terminal window. Head to advanced system settings or ubuntu tweak to change to the theme you selected! Am hoping this helps as from all my experience with OS's is that the looks are a great percentage of what makes you appreciate the system! Just want to make sure you can enjoy this OS for all its greatness! If you need any more help will do my best to help.