Adding to that, I'm often bitten trying to search for user strings because they're split across lines to adhere to 80 characters.

So if I'm trying to locate the error message "because the disk is full" but it's in the code as:

  ... + " because the " + 
    "disk is full")

then it will fail.

So really, combining both our use cases, what would be great is to simply search for a given case-insensitive alphanumeric string in files that skips all non-alphanumeric characters.

So if I search for:

  Foobar2

it would match all of:

  FooBar2
  foo_bar[2]
  "Foo " + \
    ("bar 2")
  foo.bar.2

And then in the search results, even if you get some accidental hits, you can be happy knowing that you didn't miss anything.