Okay I am very very paranoid about this. I have a decent sized amount of bitcoins to my name right now but they're spread out all over for safety's sake (in several market sites, mining pools, couple of wallets)

Where do I start to make sure my client is secure?

Should I not run my bitcoin client containing BTC online 24/7?

What suggestions do you have to secure my wallet?

What do you do to secure your wallet?

I already do:
password protected encrypted backups to multiple sources
shut down my PC at night that has the client on it
change my passwords often for mining sites and selling sites