First app I install is LittleSnitch:
http://www.obdev.at/products/littlesnitch/index.html
I usually then just browse the apple download site [
www.apple.com/downloads ] for widgets and apps which are relevant to my usage, obviously everybody's usages are different so just spend a while reading through what each app does and if it's relevant to your uses or not.
@ the OP, would you be a little more specific with what you will be doing with your Mac(s), that would enable folks to offer up suggestions of a more relevant set of apps to you because there are
so many available it's almost impossible to recommend "must haves" that'll suit everyone.
Just give us a few more details of use . ...btw I'm just going through setting up my new Macs with apps at the moment too so I'll edit this post to include what I put on my machines over the next few days......
I donate to the developer on the free apps i use regularly.
Flip4Mac [free
Firefox 3.0.9 [free
VLC [free
Transmission [free
Duplicate Annihilator [working demo
Intaglio [shareware I picked up as part of a macupdate / macheist bundle promo a while ago
Amadeus Pro [ shareware from macupdate / macheist promo bundle
Dropbox [free 2Gb with upto (by sending referrals) 5Gb total storage for free -paid service available
(PM ME FOR REFERRAL_ WE BOTH GET EXTRA SPACE)
Onyx [free
TechTool Deluxe [ via appleare
DivX player [ free
CoconutBattery [ free
GoogleEarth [free
Doozla [ 30 day demo
OSXImageResizer [free
Asteroid [free
I will continue to update this post.
WireTap Studio [ 30 day trial
PaintBrush 2.0 [free
Just found the site below, it has a list of OS X apps:
http://macspecialist.org/content/articles/essential_apps/
NeoOffice 3.0 [free
AlarmClock [free