vi

Text Edit

Smultron: http://www.peterborgapps.com/smultron/

Komodo Edit: http://www.activestate.com/komodo-edit

Voice/Video Calls

Skype : http://skype.com

Google talk (browser plugin): : http://www.google.com/chat/video

G+ hangout

Web Browser

Firefox: http://www.mozilla.com/en-US/firefox/fx/

Chrome: http://www.google.com/chrome

Twitter Client

A Plus: http://www.aplus-app.com/

IM

Adium: http://adium.im/

Office Documents

Libre office: http://www.libreoffice.org/

Video Player

VLC: http://www.videolan.org/vlc/

Miro: http://www.getmiro.com/ ( an excellent stream and bit torrent client as well)

VOIP

Express Talk(free edition) : http://www.nch.com.au/talk/talkmaci.zip

Virtulization

VMware Fusion : http://www.vmware.com/products/fusion/overview.html

Sun Virtual Box (free): http://www.virtualbox.org/

Parellels: http://www.parallels.com/

PDF viewer

Adobe Reader: http://get.adobe.com/reader/

Audio Editing

Audacity: http://audacity.sourceforge.net/

Disk burning

Burn: http://burn-osx.sourceforge.net/

Disk Image backup

Carbon copy cloner: http://www.bombich.com/

VNC client

Chicken of the VNC: http://sourceforge.net/projects/cotvnc/

IPSEC VPN

Cisco Any connect

Subversion

Command line as always

Cornerstone, good if you require an interface: http://www.zennaware.com/cornerstone/index.php

Image Manipulation

GIMP: http://www.gimp.org/

Picasa: http://picasa.google.com/mac/

Xee: http://wakaba.c3.cx/s/apps/xee

Password Management

KeePassX: http://www.keepassx.org/

GPG Key Chain

MAC GPG: http://macgpg.sourceforge.net/

Terminal

iTerm: http://iterm.sourceforge.net/

The default terminal is really nice in Lion

Mail

Thunderbird: http://www.mozillamessaging.com/en-US/thunderbird/

Diagram

OmniGraffle: http://www.omnigroup.com/products/omnigraffle/

Packet Analysis

wireshark: http://www.wireshark.org/

./arun