Following on from this Meta TeX SE question, how about offering an SE-branded pastebin for posting long files? The problem with using things like pastebin is that files get deleted after some time. Since the idea of these sites is to build a repository of questions and answers, it's no good for our answers rely on broken links.
Ideally, "SE pastebin" would have the following features:
Items not linked to by questions/answers on any SE site would be deleted.
Users would be able to control when files expire (e.g. if you're posting output from dmesg or the like, that can expire when you accept a solution, but if the text is, say, code used in the answer, then that should never expire).
Users should be able to specify syntax highlighting.