tl;dr Dropbox, Evernote, Grab, Pixelmator, CrashPlan
Dropbox: Awesome for accessing data across all my mobile devices. Kind of a swiss army knife of web storage because of all the other things you can do with it. I myself have used to to host images, create custom icons for my iPhone homescreen, sync iPhone apps to it(i.e. a notes or password manager app), share files, and host a simple static webpage. That is just what I have done with it, I’m sure there are many, many other ways to use it.
Help yourself to my Dropbox referral link if you don’t already have the service: http://db.tt/wsG9HlAJ
Evernote: I still hand write a lot of my notes as I feel it helps me retain information a bit better. The downside to handwritten notes is that they aren’t searchable and you would always have to carry the notes with you for it to be useful. My solution to this is to write my initial notes then catalogue them away in Evernote for easy searching and accessibility. The other benefit to this approach is that I’m going over my notes twice, once while writing and then again when typing them in to Evernote.
Grab: Grab is a utility built into OS X that provides the same functionality that the Windows 7 Snipping Tool does. At work I am stuck on a Windows XP machine and I have yet to find an acceptable screenshot program that matches Grab or Snipping Tool’s level of functionality.
Pixelmator: One problem for me moving to Mac was that it does not have a built-in Paint-like program. I use Paint pretty sparingly on Windows but it’s perfectly for me if I need to draw an arrow on a screenshot or to sloppily add a mustache to a cat. Within an hour of playing with Pixelmator I was able to match my productivity on MS Paint with it. Again, “productivity” is a pretty relative term here as I use Paint mostly to mess around but I am now as competent with Pixelmator as I am MS Paint.
CrashPlan: My backup solution before CrashPlan consisted of data backed up to various hard drives with many of them having duplicate or out-of-date data. Not a great system to say the least. Can’t remember exactly where I first heard of CrashPlan, possibly an ad from the free version of Evernote I’m using, but I decided to give it a try. Very happy so far. Great pricing, cross-platform, and very easy to use. Also has an iPhone app that lets you can check backup progress as well as browse and download files.