As some of you may know, SWMBO and I have a serious religious difference: she is Macintosh, I am PC.

Her current old 17" iMac has died the death that all of that generation go through: the display is failing with (by now) about two dozen vertical lines. She now uses a 20" iMac that is... troublesome.

Yesterday I purchased for her on eBay a used 24" iMac. Aluminum case, 2.8 GHz dual-core Intel processor, 6GB RAM, 2 TB hard drive, 256MB video. Not at a bargain price ($850) but I think fair for both parties.

The [previous] owner nuked and repaved for me, and has installed Lion OS (OS 10.7), the original iWork08, MS-Office 2011, Chrome & Firefox browsers, and Adobe Photoshop Lightroom 3. He is also sending the original installation discs for Leopard (OS 10.5) that came on the computer when it was new. He apologized for not updating the OS to Mountain Lion but from what I have heard about 10.8 I should consider that a blessing.

This will be SWMBO's third iMac. Her used 20" now has enough problems the less said the better, but we got it so cheaply that it doesn't distress us too much. Probably a nuke and repave would fix most of the deficiencies, but not all of them. This new 24" is her first "clean" iMac, that is just a bare operating system and a couple of apps, no crapware [yes, Bruno, I know you think Firefox qualifies ], no mistakes inherited from previous owners, etc.

Are there any Dos and Don'ts I should be aware of in setting up this computer? I can choose among OS 10.5, 10.6, 10.7, or (for another $20) 10.8. Is the currently installed 10.7 good? About all I know about Macintosh OS is that it drives me up the wall because it's different from what I'm used to. I have plenty of time to think about this, it will be at least three to four weeks before it gets through customs and delivered here.

Suggestions/recommendations will be appreciated.

tanstaafl.

With that much ram, 10.8 will run fine on it. Apple has released 10.8.2 ( essentially a second service pack now) so many of the shipping quibbles people had have been addressed. Ignore Bruno's whining ;), for what your wife needs, it will work fine. Been running it since release with no major issues.

Easiest way to go about it is to get 10.8 first, (Apple Menu, Mac App Store) let it run the upgrade, then after the upgrade run the Migration Assistant (click the magnifying glass in the upper right to search, type in Migr... Until it comes up, then click to run). It's is a painless way to copy over any of her data from either Mac, right over the network. Simply run it, read the instructions to pick what to migrate and let it run for a little bit.

*edit*. Migration Assistant also works to pull data from Time Machine backups she may have from the older macs. Pick whichever route is easier, network, or using he backup drive.

Migration Assistant was also really nice for moving my mom from XP to OSX, if I'm remembering correctly.