We all have our must-have apps. Whenever we re-install our system, these are the first apps we want to get in so that we can get back to business. From time to time we discover new apps that are really mind-blowing and we wonder how we survived without them. For me, 1Password and Visor are two apps like that.

Since we all have different must-have apps, I thought I’d share a list of the Apps that I consider must-have apps for Mac OS X.

A super-handy password-manager. For a long time I used Keychain for this, but after coming across 1Password, I wondered how I survived without it. It’s super neat, can be configured to synchronize with Dropbox and is available for iOS and Android too. Password management have never been this easy.

A great IM client for more or less all instant network services (including, GTalk, ICQ/AIM and MSN).

A very handy tool for installing Unix/Linux-tools. I use it to install tools like Git, Joe, Nmap and Wget.

Goes without saying.

Like Microsoft Office, but without the bloat and created by people who have a sense of design.

A great tool if you are as paranoid as I am. This tool acts as firewall for outgoing connections. As soon as an application tries to make a connection to the outside world, LIttle Snitch will pop up and ask you if you want to allow the connection or not.

The best best tool around for plotting out workflows and structures. I use it a lot for making workflows of networks and applications.

The de facto standard VoIP tool today. Get the unlimited calling plan and a Skype-in number, and you have your phone with you wherever you go.

Great social network aggregator. Allows you to follow and post updates to Twitter and Facebook.

The reason why I never use iTunes anymore. Unfortunately it is not available in the U.S. yet. It is also available for iOS and Android.

A very handy and flexible text-editor. It is a bit pricy, but it will probably increase your productivity if you write code.

A GTD-style todo manager.

The tool that takes FTP/SFTP/S3 to a whole new level. Works like a charm.

A brilliant add-on to Terminal. Creates a drop-down terminal that is triggered by a hot-key. I love this tool.

Probably the best desktop-virtualization tool on the market.

Installs Apple’s development tools, and compile tools such as GCC.

Update: I forgot to add VideoLAN to the list. In case you’ve been living under a rock for the past few years, it’s great video-player.

Update 2: Airfoil is another great app I forgot to add to the list. It enables you to stream music over the network to other computers or to an Airport Express. I use it both at home and at the office.

Update 3: Our app Blotter is obviously also a must-have application for OS X.