Another Windows 8.1 user here. Three freeware programs I find incredibly useful are:
CCleaner, which keeps the unneeded temp files, broken files, obsolete log files etc. cleaned off the hard drive.
Speccy, which can be configured easily to keep the current CPU temperature resident in the system tray; it also is a very reliable source for hard drive S.M.A.R.T. data, if your hard drive is so configured.
File Hippo’s App Manager, which monitors the currently installed versions of many free programs & utilities (like Java, Flash Player, etc) and then provides a list of programs that need to be updated.
All three of these programs can easily be downloaded from filehippo.com.
In addition I also keep Sysinternals Process Explorer active & resident in my system tray as well, where it gives me a graphical look at CPU activity, physical memory use & commit charge use. In addition, its full display gives detailed info on all of the currently running processes, and provides an easy way to close programs that have frozen & quit working.
For a browser, I recommend Firefox over Internet Explorer, which is officially being replaced by something new in Windows 10, out later this year.
As far as productivity suites, if you are ok with Word, then stick with it. However, Word Perfect is much easier to use.