Maximum PC has a site that recommends the 32 Totally Essential (and Free) Apps for Every New PC. This list, covering 7 pages, spans the full gamut from Utilities, to general Applications. Windows Appstore, while having fewer apps, lists the Top 20 Free Apps for your new PC. While this list is smaller, and has some of the same apps as Maximum PC, it lists them all on a single, page, and provides a large screenshot of each app, so you have an idea of what they’ll look like on your PC.
Another good site is Guiding Tech’s Top 10 Free Software Apps to Install on Your New PC. This list includes CCleaner (Crap Cleaner), which is great for removing tempory and other junk files off your PC. Running CCleaner frequently can help keep your PC from slowing down.
Keep in mind that these lists continue to change. It’s also important to update apps on a regular basis, because as time goes on, updates are released to address bugs and security concerns. Always use Windows Update to make sure your PC has the latest security patches.