I tend to find it fascinating to see what other people use, plus its a great way to discover new apps you didn't know about

I'll start it off

Click for full size - Uploaded with plasq's Skitch

Here are mine (from my iMac, which has the most of my machines)


Click for full size - Uploaded with plasq's Skitch

What are your most used apps ?

For me, the list of most-used apps are:

1Password (every day - for logging onto websites and getting my banking details, etc)

Brightness Control (used every night - as the iMac is in our bedroom)

ChronoSync (backs up my iTunes Library onto the Drobo every day)

DropBox (every day - for syncing most important files across all my Macs)

EyeTV (every day - for recording TV shows)

GimmeSomeTune (runs in the background and used for getting the lyrics to new songs I've bought in iTunes)

iAntiVirus (have it running in the background and doesn't seem to be slowing the iMac down)

iBank every day (it's not on my iMac but on my MBA) - miss MS Money though  

iPhoto (every week or so - when I have new photos)

iTunes (every day - as I use it for picking up podcasts and TV Shows)

iWeb (every week - at least until I cease blogging)

LaunchBar (every day - can't live without this now!)

Mail (every day - pretty obvious as to the reason why)

NetNewsWire (every day - great for consolidating all the RSS feeds I'm interested in)

Pages (every week or two - whenever I want to write pretty letters!)

Remote Buddy (every day - for controlling the iMac in bed)

Safari (every day - like right now!)

Skitch (every few days - for posting to this Forum, mainly)

Time Machine (every day - hourly backups of all my machines)

Twitterrific (every few days - I try to stay away so I don't get addicted!)

Vienna (every couple of days - it picks up feeds really quickly vs. NNW when you refresh but I only use it to review a couple of my favorite feeds)

Leaving out the mac apps:

List of Installed Applications
--------------------------------------

in no particular order

Speed Download
Launchbar
SuperDuper
Growl
iStat menus
Coversutra
Handbrake
Toast 9
iPhoto buddy
Skype
Spamsieve
Pixelmator
Airfoil
Firefox/foxmarks
1Password
Mail act-on
Mail tags
Letterbox
Mercury mover
Bento
Miro
Appzapper
Busysync
Quicktime Pro
iBank
Textexpander
Hazel
Evernote
Dropbox
Startuppref pane
Perian
WMV from flip4mac
Album art thingy
VLC
FlickrExport
iGlasses
Twitterific            
Metax
Remote Desktop Connection
Cyberduck
Drive Genius
Rapidweaver
Default Folder X
VirusBarrier X5 (uninstalled)
MacGourmet Deluxe
Little Snitch
iVolume
KeyCue
MacPilot
WhatSize
iDive
Skitch
Comic Life Magiq
MacParDeluxe
NZBDrop
Inquisitor
Dupin
Join Yogether
Make Bookmarkable
Things
Awaken
Chronosync      
Caffieine      
SoundSource
Imagewell
Teleport
Fiwi
Magical
Colorflow(icons)
SpaceSuit
DockSpaces      
Witch      
Warp
iWork09
Houdahspot
Houdangeo
Tooble
Securefiles
VirtualBox with
     Windows 7
     Unbuntu 8.10      
     Windows XP      
TextWrangler
PhotoPresenter
iTalk Sync / iTalk iPhone
iPhoto Library Manager      
onyz
google earth

You're welcome Phil re GimmeSomeTune.

Here are a couple of comments regarding it:

1. Sometimes the lyrics it pulls back are not 100% accurate so you may have to correct the odd line or two.

2. It works well with the AppleScript "Needle Drop", which I left running during the day (having it change the music track every 5 seconds) and it put lyrics into probably 90% of my music library.