I don’t ever comment but after reading the above commenters (artisticJellyfishKM) post, I just have to say that he is completely wrong. You will never get a virus just because you shut down your computer, that doesn’t even make sense. Also, do’t fall for the hype that macs can’t get viruses. If you’re on the internet, stay away from shady looking websites that are asking for unsolicited personal information, asking you to download some random video codec, and etc..
As for the sleeping vs shutting down issue. It’s really up to you. Contrary to what other people have said, shutting down and restarting your computer will not wear down your computers components. There’s really no such thing as a “cold” start with computers unlike cars. Sleep mode will use next to no power at all, but when it’s shut down completely it will of course use none. Depends on if you want to wait 1 minute for it to turn on again, or a few seconds to wake up from sleep mode.
As for some actual useful info, I suggest you check out
Hack Attack: A guide for switching to a Mac
Top 30 mistakes made by new Mac users
Some general tips from me. Make use of apples unique window management. You’re probably used to alt-tab on windows for getting around (apple has to that too, but the short-cut is command key+tab) which is fine and all. But I use expose and spaces to get around. You have to set up your own short-cuts in the preference , but totally worth it.
Also, when you click to close button on an app, be aware that this doesn’t actually completely quit most apps. It will close the window, but the app will still be open. Some people find this annoying, but if you want to completely close out an app, select quit app from the top menubar, the dock, or hit command+q.
One misconception people have about macs is that they can’t right click. Not true at all. Plug in any usb mouse (even if it’s not explicitly made for mac) and it will just work, right click button and all. This goes for a lot of usb peripherals also.
As for software, yes it’s true that there isn’t as much software available for the mac as their is for windows. But at the same time, there’s at least 1–2 good apps that cover everything you need. Microsoft even has their office suite on mac, threre’s apples iwork if you won’t want to use microsofts stuff for publishing, there’s also the free and open source open office if you don’t want to pay at all. I don’t know if you’re into a creative professional of any sort, but there’s also software for that. Adobe, Avid, and Autodesk all have cross platform versions of their apps. Apple also has Final Cut and Logic studio (with cheaper express versions available too) for video and audio editing.
There’s certainly no shortage of web browsers. Of course you can stick with apples own safari, which is pretty good and fast on macs (can’t say the same for the windows version), but then theres also firefox, google chrome, and opera just to name a few.
For instant messaging there Adium it covers all the major Im protocols (aol, msn, yahoo, google talk) but it also has customizable themes and such. For some reason there’s a ton of twitter clients for mac. To many for me to list, but a quick google search and you’ll find at least a dozen if you’re even into twitter at all
For music playback. I really don’t think there’s anything better than itunes on the mac. The windows version is so-so, but the mac version performs well. If you’re not into itunes, you can check out Songbird It’s sort of like the firefox of music players, it has extensions, but you can make it buggy and bogged down if you install too much.
For video playback, I never like quicktime, even on macs themselves. There’s the all mighty VLC that will play everything under the sun. Personally I prefer Movist it will play pretty much everything VLC can play, but it has a more “mac” feel to it. If for some reason those two players don’t play a video, you can install Perian which is a bundled codec pack
If you’re not satisfied with Finder for file management and browsing, I suggest you check out Path Finder . Think of it like finder and windows explorer on steroids. It has tabs, duel pain windows, and a bunch of other features that make it really useful.
If you’re really feeling adventurous you can check out Leap by ironic software. It’s not really a file browser like finder or windows explorer, but rather a way to search and find files by tags. You may or may not be into it, but it’s worth checking out.
For some small, quirky apps I suggest checking out
Istat Menus (Lets you see your cpu, ram, hard drive etc… use in real time)
Caffeine (prevents your computer from going to sleep when inactive, useful when watching videos on the internet while no in fullscreen)
Cinch (this little app emulates the windows 7 feature of dragging a window to the side of the monitor and making it take up exactly half of the screen, pretty useful with high resolution monitors like your imac)
Growl (notifications from apps in a customizable popup in the corner of your screen)
Transmission Small lightweight bittorrent client
Whew, I hope this isn’t too much too read, hopefully you get something out of this post. If there’s anything I didn’t cover, a quick google search will prolly get you answers. If you want more software, I suggest going to macupdate or version tracker directly and searching