If the 90s ushered in "The Information Age" then I believe the period in which we currently reside is "The Managing The Information Age." Now that our lives are woven together by a tapestry of multiple devices, the real currency of information lies in our ability to have it up-to-date wherever we need it. The following list is my personal arsenal of sync sorcery:
MobileMe - For social & work data - Truthfully, I haven't had any problems with it (except with 3rd party software that piggybacks the sync, but I'll get to that). In fact, before iPhone 2.0 I had been complaining that there should be a wireless syncing feature. Whenever I change a date or contact on my phone it changes on all my machines. Most people don't like the $99 price tag, but I always like to look at cost vs. utility, and I use this multiple times a day every day---it's worth it to me. I have to say, though...something about "me.com" is irritating as a moniker. Dot mac had a nice flow to it.
MacJournal - For notes & non-script writing -Used to sync beautifully through .mac but has since turned on me (as referenced above) . Fortunately, I just installed version 5.1 which is supposed to address this issue.
1Password - I just don't know what kind of existence I led before this application. 1Password from Agile Web Solutions syncs your passwords across multiple browsers on the same computer (you have to do a little drag-and-replace file action to get your passwords across multiple machines, though) and the iPhone app is super mega kick-ass. It not only stores your passwords but also will generate them if you want something more secure than "12345abcde" and has an amazing autofill feature for every username/password field. If you really, really trust it, you can enter credit card numbers and personal info so you can autofill those fields as well.
Foxmarks - Tired of that web-based del.icio.us business? I don't know why you would be, but if you want to keep your bookmarks local then you've hit the honey hole with Foxmarks! Originally, this was an add-on for Firefox but they apparently have an IE version now. Not sure if they cover Chrome yet. I'm guessing not. And I'm a good guesser.
Chronosync - Just your basic backup file sync program. Yes, I use Time Machine but I also have a small 250g travel drive as an extra backup for the most essential files. I'm a compulsive backerupper and I admit it.
Busysync - This luscious pile of hotness syncs all of your calendars from your iCal to your Gcal. It also syncs Bonjour across a network, but that doesn't affect me and this is my blog so just forget I mentioned it.
OmniFocus _ Productivity Titans OmniGroup offer this terrific program that is based on David Allen's GTD religion. The sync part comes in with the nifty iPhone app that seamlessly poops all of your todo and active project information back and forth between your phone and computer. A Jott to OmniFocus hack has also been created to free up your tired fingers. OF's support guys are also super nice and on the ball, which are features I enjoy in a software company. Other features I enjoy in a software company: mustaches.
Now go! Share your data with yourself!