Is Indexing HD a good Idea?

Your computer should automatically start indexing and I'd personally recommend it as it lets you search your HDD very fastly.

You may me interested in Find Any File from: http://apps.tempel.org/FindAnyFile/

Find Any File is a program for Mac OS X that lets you search for files on your disks.

• Contrary to Spotlight, it does not use a database but instead uses the file system driver's fast search operations, where available. This lets you search for file properties such as name, dates, size, etc, but not for file content (use Spotlight or EasyFind for that).
  
• Find Any File can find files that Spotlight doesn't, e.g. those inside bundles and packages and in inside folders that are usually excluded from Spotlight search.
  
• Finally, it is quite fast. A search only takes a few seconds on an internal hard disk or SSD. Try for yourself!
  

Find Any File doesn't replace Spotlight, but it complements it greatly:

• If you search for content, such as in e-Mails, PDFs, Word docs etc., use Spotlight.
  
• If you search for files by name, size or date, use FAF, as only then you can be sure that everything available is found.