Xmarks - This is great to keep bookmarks synchronized between different machines and also to keep them backed up in the cloud.Quicksilver - Fantastic app to do more with less work. Recently it has seen new life, it is rock solid on Snow Leopard. It has a lot of goodies (like triggers, plugins) and pretty soon you’ll be a keyboard ninja operating your Mac.Dropbox - Just Wow!TextExpander - This one of those must have apps. Great to create form letters, emails, etc… TypeIt4Me is also a great substitute, I have both of them and they are equally good.BetterTouchTool - It’s like TouchPad Pro for your Mac. Expands the multitouch capabilities of the touchpad. Really useful.QuickCal - I learned about this little gem on Mac Menu Bars. Lovely little app that allows me to check my calendars and todo’s and with a quick shortcut key allows me to enter events in plain language. Really useful. Works well with BusyCal because it shares the iCal database, but the developer is working on a better integration with BusyCal.ClipMenu - ⌘-C ⌘-V for the Pros.LittleSnapper - Screenshot utility with powerful sharing and editing features.QuickCursor - A quick way to launch my favorite no distractions text editor (WriteRoom) from any app.Hazel - Another must have little gem. It automates a lot of folder cleaning and organizing stuff.BusyCal - It is often described as iCal Pro, and in effect it is. The way it syncs with Gmail is alone worth it.Bluetooth, Airport utility, Sound and Battery Status, all stock Apple items.FuzzyClock - FuzzyClock is great. It gives you the time but in a more human reading form. (From Pedro Fonseca)

Xmarks - This is great to keep bookmarks synchronized between different machines and also to keep them backed up in the cloud.
Quicksilver - Fantastic app to do more with less work. Recently it has seen new life, it is rock solid on Snow Leopard. It has a lot of goodies (like triggers, plugins) and pretty soon you’ll be a keyboard ninja operating your Mac.
Dropbox - Just Wow!
TextExpander - This one of those must have apps. Great to create form letters, emails, etc… TypeIt4Me is also a great substitute, I have both of them and they are equally good.
BetterTouchTool - It’s like TouchPad Pro for your Mac. Expands the multitouch capabilities of the touchpad. Really useful.
QuickCal - I learned about this little gem on Mac Menu Bars. Lovely little app that allows me to check my calendars and todo’s and with a quick shortcut key allows me to enter events in plain language. Really useful. Works well with BusyCal because it shares the iCal database, but the developer is working on a better integration with BusyCal.
ClipMenu - ⌘-C ⌘-V for the Pros.
LittleSnapper - Screenshot utility with powerful sharing and editing features.
QuickCursor - A quick way to launch my favorite no distractions text editor (WriteRoom) from any app.
Hazel - Another must have little gem. It automates a lot of folder cleaning and organizing stuff.
BusyCal - It is often described as iCal Pro, and in effect it is. The way it syncs with Gmail is alone worth it.
Bluetooth, Airport utility, Sound and Battery Status, all stock Apple items.
FuzzyClock - FuzzyClock is great. It gives you the time but in a more human reading form.
(From )