I don't have a lot of time right now, I will come back and fill out the list with the whys and wherefores tonight.

EDIT: Linkage plus explanation as to why each made my top 10.

1) QuickSilver - I am in the process of writing a tutorial/walkthrough to explain why I think so highly of QS. I hope to have it done some time next week. In the meantime check out these articles.

2) ShapeShifter - because I like to have a more consistent look and while I think the default theme is OK, there are better.

3) WindowShade X - because I am used to being able to shade applications from Linux. The additional features (always on top, minimize in place, make transparent, etc...) are just a very handy bonus.

4) iStumbler - I do quite a bit of network trouble shooting and have set up multiple wireless networks professionally. This is a great tool for gauging signal strength and gives you a reasonable idea of how far a network can reach. Oh, and it is good for war driving as well.

5) Transmit X - great FTP app. Not much else to say here.

6) Witch - mainly I got this because it allows me to set a hotkey for zoom. The ability to tab through individual windows (rather than just applications) is great though.

7) SideTrack - Your trackpad on steroids (if it is supported). I tap on one corner for expose, another for the dejaMenu (see below), the third for middle click, and the final corner for right click. And I assigned dragging on the right edge as scroll. While it takes some getting used to (start your mouse movements closer to the center and turn up sensitivity) it makes the trackpad much more versatile for me. If you like the single button mouse thing though i suppose this would be less useful.

8) Adium X - A great IM, supports SameTime (which my office uses)

9) Handbrake - For ripping DVDs to take with you on the road.

10) DejaMenu - Indespensible on larger desktops. With a hotkey, bring up a dropdown menu that matches the title bar at the pointers location. On large dual monitor desktops this is far easier than moving all the way across one monitor, onto the monitor with the menu bar, and up to the menu I need. Wth the hotkey assigned to a corner of my trackpad it is even easier.

NOTE: List subject to change but that will do for a first pass.