Choosing my thesis topic

Working on mahshelf, barisma, recepist, sf-resource projects sure brought me lots of experiences in web developement. I can list below a few of them and I intend to choose one of them as the topic for my thesis

1. I learned to upgrade a web app from symfony 1.0 to symfony 1.2 (mahshelf.com), that may sound simple but it was a pain in the ass due to the incompatibility between those versions. Manual changes have been made in controllers, routings and even the templates.
2. I learned to optimize a web app, both in the frontend with compressing css, js files, moving the static files to the cdn; and backend (PHP, MySQL optimization). I really had fun when doing those tasks
3. I developed a brand new web app (recepist.fi) with symfony 1.2. If I choose this topic, it will be a complete tutorial on how I have created things around this web app. However, I have not finished developing this app which means I will have to do the research and write documents at the same time. The case is not suitable since I am quite hurry and just want to write things I have been clearly aware of.
4. I am a jQuery fan. Spending time writing jQuery portfolios makes me realize that I have written several useful jQuery plugins and I should  write my thesis about it

So far there are 4 to choose from. I myself find 1) really interesting to write about since there are tweaks, hacks and lots of scripts just to get things done. However, it will be boring for the teachers who give reviews since I am pretty sure that they do not know what I am writing about. And 1) is not truly practical since hardly any web company need this topic.

2) was fun when I did the tasks. Not only they mention a lot about high performance website and web optimization on books and blogs, there are also several FF plugins and open source tools for me to finish the benchmark.  I am likely to choose this because (to be continued)