Which is the best way?


Hiya, i am medium experienced mac user running 9.0.4, on an iMac DV 400. I just placed my order of OS X form the apple store (uk) and also ordered extra RAM (128 mb taking me up to 192) And i need advice. I really cant be bothered to deal with all this partitioning rubbish, i just wanna have OS X intalled simply like Apple will do when it is their Default OS (sometime in jusly or so i heard), and is it reliable enough to install without backing up? (i have no means of backup apart from iDisk) Basically which is the quickest, Simplest and most effective Way of installing OS X without reformatting/partitioning and all that rubbish, any response would be great!
It is possible to install X on top of 9 w/o partitioning. Just make sure you do a clean install of 9.1. Also backup your documents and anything else you have that is important, use the iDisk if you have to but backup.

Enjoy X when you get it,
i have no viable means of backup apart from iDisk, if i upload appleworks documents onto idisk will they come back unformatted? i did it with xdrive.com and has to dowload them to a wintel pc and open them in wordpad, copy and past it to an e-mail and then send it to my imac, then copy and paste it into appleworks, how do u mean a clean install? do u mean wiping everything and starting over? i have 200mb worth of mp3 that i really dont wanna lose and i dont have time to upload it to idisk!
please help