I used to think that the openSUSE installer was the most flexible Linux installer, with Anaconda running a close second, but I think I’m going to at least put the Debian installer in a 2-way tie for first with openSUSE. More here

However, one thing that continues to impress me about the Debian installer is the extreme amount of choices in which to get Debian installed on your system. You can pick any path, ranging from the complete newbie-have-the-installer-choose-everything-for-you to total hacker control over what you want installed, and everything in between