I'm not sure if it is exactly what you want, but the Firefox Scrapbook
extension is quite good at scraping individual web pages and those web-pages nested underneath a page. You can tell it how "deep" to go in the nested site, and what files to pick up/ignore as it goes. It tidies all the links up when done, so you have a relatively self-contained copy of the downloaded pages.
I have highlighted in the screenshot below - using red boxes/arrow - the relevant bits of the download option (which pops up on a drag/drop save to a Scrapbook folder):
Scrapbook is useful where you want to be able to search/retrieve the content easily. Not only can you use Scrapbook to index/search all that it downloads, but also, since it saves the content in a non-proprietary format as html, you can index/search it with the standard Windows Desktop Search and
- in my case - xplorer²
(a Windows Explorer replacement tool). Any files it creates or downloads also immediately show up in the file/folder search tool Everything