One of the main problems that all of us who start using Mac OS
I have been using Mac OS for a few months now, and I think I have already largely solved this problem, since I can do exactly the same things as on a Windows computer. The following list is made up of the programs that I found to be the best in their functions.

Instant Messaging
Adium is the best substitute for Messenger on Windows, fully customizable. The only drawback it has is that it does not allow video conferencing, so when I need to use the webcam (on rare occasions), I use aMSN.
Recording of CDs and DVDs
Although you can burn data CDs directly from Finder, I have not found a way to burn (normal) audio CDs. Thanks to Ancude I have discovered Burn, a fairly easy-to-use program that has everything we need to burn audio, data or video CDs.

Image and photo editing
In this area, âswitchersâ will have no problems, since Photoshop, as in Windows, is the perfect solution. In addition, this section could also include the editing and creation of animated gifs, which can be easily done with Adobe ImageReady or Fireworks.
Audio Playback
In this area, iTunes beats the rest of the players, since unlike Windows, in Mac OS X it integrates perfectly with the rest of the system.

File Compression and Decompression
Possibly one of the biggest problems coming to Mac OS X is a decent compression utility. The problem is that we will need several programs to perform this function. For RAR files, I use two programs: SimplyRAR to compress them and UnrarX to decompress them. To decompress other types of files there is Stuffit Expander, while to compress in ZIP, we can do it by right-clicking on the file or folder and choosing âcompressâ, since it is a standard option on Macs.
Video Playback
Like Windows, Mac OS It is very possible that it would also be useful to have the DivX and XviD codecs, as well as the WMV to play Windows Media Player files (with Flip 4 Mac).

Share Files via P2P (Peer 2 Peer)
The alternatives to eMule and uTorrent, which I use on Windows, are two that have nothing to envy of their counterparts: aMule and Transmission (For BitTorrent). There is little to say about the first, except that it is exactly the same as the Windows version and Transmission is a simple and light program that will dazzle you as soon as you use it.
There is also a corresponding version of Pando, the same as Windows.
FTP Programs
For me, the best of all is Transmit, although there are others, like CyberDuck (which is free), that fulfill the same purpose. Finder can also be used to access servers via FTP.

Text Editors
Replacing the wonderful Windows Notepad++, we have Smultron, which is free, and BBEdit, which is paid.
Office automation
There is a version of Adobe Reader to read PDF files. Also, when it comes to âoffice suitesâ, we have OpenOffice, which is free and equal (or better) than Microsoft Office 2008 for Mac and iWorks (not Iwoks), Appleâs version of Office.

Other Applications
So much for the applications that we might most commonly need when starting to use Mac OS
- iShowU: Used to record the computer screen. Ideal for making video tutorials or recording YouTube videos, since it also records sound.
- Zattoo: Used to watch television through P2P. We only need an internet connection.
- Split & Concat: To divide or join files.
- Shot Choice: To be able to choose the format in which we want the screenshots to be taken
- Remote Desktop Connection: To control a Windows computer from our Mac
- Qumana: To write while we are offline on our blog
- Nokia Multimedia Transfer: Used to transfer files from a Nokia mobile to the Mac and vice versa. It is interesting because it allows you to synchronize iTunes with your mobile.
- Netfixer: To capture entire web pages with just one click.
- Last.fm: Listen to songs that match your groups and create your own musical profile.
- Google Notifier: Used to receive Gmail and Google Calendar notifications on the desktop.
- Eclipse: To program in Java and C.
- Startup Sound: To remove the MacBook startup sound.
Thanks to Aitortxu, who has left a comment on menéame in which he lists some of his essentials.
- Perian: Codecs for CoreVideo and QuickTime.
- The Unarchiver - Decompresses everything not like the stuffit expander shit.
- Bean: Free word processor.
- VisualHub: Video editing.
- Colloquy: IRC client.
- POV: SuperPuzzle Free.
- FFView and SimpleComic: Comics Viewers.
- TVShows: Automatic download of TV series.
There are also many people who say that Quicksilver is a must-have, although I personally use Spotlight which performs practically the same functions.
And here are the applications that I consider essential for Mac OS X. Would you add any? ;)