Assume nothing is safe!
I see alot of posts on using Armory however what good is Armory if you haven't verified whether the file has been tampered with?
I highly recommend installing a Linux Distro.
1) Download Linux Distro
2) Checksum .iso file with ALL relevant hashes (sha1,md5,sha256,etc..)
3) PGP your .iso file as well comparing to the public key the developers produce.
4) Set aside a machine for purely storing your BC.
5) Install Linux (do not install third party drivers)
6) Remove any tracking features if enabled (Newer versions of Ubuntu sends your data to amazon..... general command is "sudo apt-get remove unity-lens-shopping").
7) Install UFW and reject all incoming connections whenever you start up your machine. (You can get more technical for allowing/denying/rejecting connections via terminal or the preferences section of UFW)
Add various trusted Firefox addons (I'll compile a list later on in this thread).
9) Download your preferred wallet
10) Check sum your preferred wallet with ALL relevant hashes.
11) PGP your file once again and compare it against the developer's key.
12) You now have a very secure system.... If you'd like to go more in-depth you can always check out Hardened Linux.