Remote Control & Front Row
The most defining feature of the new iMac must be its remote and Front Row. The remote is held in place on the right side of the screen using a magnet, and it looks like an iPod shuffle with an extra button named 'menu'. With it, you open Front Row.
Now, what exactly is Front Row? Simply put, Front Row is 'nothing more' than a front-end for iPhoto, iTunes, Quicktime Player, and DVD Player. Front Row even loads those applications when you browse through the menu. So, Front Row offers no more basic multimedia functionality than the applications it launches. Front Row literally is no more than the sum of its parts-- when it comes to playback/viewing that is (seeing edit and download functions aren't available in Front Row).
However, that does not mean Front Row is a useless application, because quite frankly, it's not. It is very easy to use, it looks good, and the readability is excellent for when you're not sitting right in front of your computer. I can imagine Front Row being really awesome when you're throwing a party.
The remote control simply is a joy to use. The furthest distance away from the iMac I could try the remote from, was about 7 metres, and it had no problems with that distance at all. Also, the 'receivability' (yeah I just made that word up) of the remote is excellent; there is no need to aim at the receiver directly (which is placed behind the Apple logo on the front bezel of the iMac). You can also use the remote without Front Row; you can control iTunes with it, or DVD Player, or whatever. It can also sleep/wake the iMac. What I miss is some sort of configurability; it would have been nice if Apple included a panel in System Preferences with which you could change the behaviour of key-presses (ie. load iTunes when 'play' button is pressed). For more advanced 'remote controlling' of your Mac, I suggest the outstanding Salling Clicker.
However, Front Row also has its drawbacks. For instance, it does not update your podcast subscriptions. It does not give you access to the iTunes music store (which I do not use anyway, but still). Because Front Row's sections need to load their respective applications, it can be slow. It does not shut down those applications when you turn off your music-- so when you exit Front Row, iPhoto, iTunes, and so on are still running. The delay between pressing the 'menu' button on the remote and the appearance of Front Row is also too slow, which sometimes leaves you pressing the menu button twice.
Some people (including Steve Jobs himself) compared Front Row to Windows Media Center Edition. This makes no sense at all, and it's a gross overstatement of Front Row's capabilities. The comparison Jobs made during the announcement of the iMac G5 between a remote for MCE and the iMac remote is completely out of this world, and makes absolutely no sense at all-- it would be like comparing the remote of your garage door to the one of your TV, and then claim usability supremacy because the former only has two buttons. MCE sports all sorts of features that the iMac with Front Row does not have, with the most important ones being TV and TV recording functionality. And there we have the new iMac's major, major weakness: the lack of support for television viewing and recording.
When I first saw the new iMac G5 in that special press event, the first thing I thought was: where is the TV support? The machine is perfectly fitted to be a television: remote control, widescreen, instant sleep/wake functionality. The lack of it is a big failure of the new iMac G5, and seriously damages its value when you already own a previous model. Personally, I would have bought the iMac immediately if it wasn't for the lack of TV support. A major miss by Apple; the people at MacSupport confirmed that there is great demand for this functionality, and it wouldn't surprise me at all if something like this will be announced tomorrow during Steve Jobs's keynote.
In conclusion, Front Row is a nice application, it does what it is supposed to do, and does so in an easy, beautiful way. However, don't expect that you can use this iMac as a replacement for your TV-- something some people have been hinting at. And it's by far no competition for MCE in terms of functionality.