Your software needs are based on what YOU want to do with your PC--music, art, creative writing, games, whatever. I have compiled a list of what I consider "Best-of-Breed" software for Windows:
Read more: http://askbobrankin.com/what_is_picasa.html#ixzz1gSBY2E2d
Video & etc
Internet and Search
Tools and Other Helpful Software
You can download CCleaner from Piriform website. Also check out their other software products that I also helpful and that I too trust.