What is your favourite tool for impact analysis?
Especially in the the context of web-applications where an IDE cannot always help you considering that your code references might be in at least 4 languages (java, jsp, velocity templates, javascript, html and the ominous xml).
Thus far I've managed with find and grep are there any better?
See our Source Code Search Engine. It can "grep" across multiple language, but it knows the language syntax (comments, keywords, strings, variable names, numbers, ...) for each and can thus focus your search more carefully. For web page analysis, it knows PHP, JavaScript, HTML, C#, Java, JSP, as well as C, C++, COBOL, Fortran and other languages. By indexing all the files according to langauge tokens, it can handle searches across 25-50 million lines of code nearly instant response times. It shows matches, and provides single-click-to-view-source on each match.