I have the same experience in both front-end and back-end development, but I quickly learnt that designing and implementing UI is the most exciting part of my job for me, so I would like to extend my skills in that field. I also have a little bit of experience with designing databases, but mostly on non-commercial projects.
I am a bit pedantic so I am trying to be a perfectionist at work. I often find myself working on UI on my own, as an addition to other tasks, because I don't like when something feels like it is not fitting the big picture.
I believe that the quality of the application should be measured equally by how stable it is, how good it looks and how easy it is to use it.