1.Disable Flash on everything but youtube(or anything you deem safe)
2. Disable or delete Java.
3. Don't download cracked programs OR download only those older than 2012 or older.
4. Don't store your wallet on Dropbox.
Follow above steps, and you don't even need to run an anti-virus, which is btw, recommended. You can thank me when your 1btc you kept safe is worth $100k.
5. Encrypt your wallet with a strong password, 10 - 15 chars in length with random characters. Do not store your wallet and password in the same storage
6. Install no-script addon to protect our computer from malicious scripts when visiting untrusted site
Encrypting the wallet does nothing if you install a keylogger. I will let you on a secret. These 3 years, I've never encrypted my wallet, don't even have an anti-virus but my computer is squeaky clean. I just follow those three steps above.
I've also gained the skill of reverse engineering allowing me to peek into the assembly of potentially malicious exes before I run them. I've also thought of implementing custom software to specifically protect from suspicious programs reading wallet.dat or installing keyloggers.
This software would be nice, I don't think there's a program like this on the market / on the web.