Which File System Is Best For Me?
Different filesystems have somewhat different features and strengths and/or weaknesses and a system admin selects which one to use based on how the system is going to be used and which filesystem best suits those needs. You're not just limited to the ext(x) line either, there are also ReiserFS, XFS, JFS, FAT32, NTFS etcetera.
So, only you can determine what will work best for you and your situation. Questions like this often turn into "religious wars" as people argue back and forth about their personal favourite and, in my opinion, that usually is unproductive. If you want to research a bit and ask a specific question about a particular system, then that might be productive and get you useful answers. It always a wise approach to a question.
Here are some links to get you started:
This question is coming up more often in relation to ext4 since it's now an option in Jaunty. Conventional wisdom would say it's too early yet to use it, unless you really need some of it's benefits now.