If you have more than 1000 Bitcoins in your wallet:

1. get yourself a low cost netbook.
2. Install not bloated linux (like archlinux) or FreeBSD or OpenBSD (in order of growing paranoia).
   - make sure that the above is done with ecrypted partitions and swap (plenty of guides on the net).
   - make sure that the above is done while offline as much as possible (for truly paranoid ones).
   - make sure that you do not not even configure wireless hardware, let alone using it
   - physically plug in Ethernet cable when you need connectivity for a minute or so
3. Install bitcoin client, generate a bunch of bitcoin addresses (current account)
4. Over time transfer in small amounts your funds from your existing client to the addresses created in step 3
5. Keep this used exclusively as bitcoin client and nothing else, plug in Ethernet cable when you need to transfer money.
6. Keep this hardware wallet safe.
7. Creating a bitcoin savings account and making secure backups is still need to be done as described in multiply guides elsewhere.

P.S. Do not forget your passwords.