1st, Merry Xmas and congrats on your new toy
2nd, Welcome to the forum...
3rd, for the touch pad, rightclick on the icon in the system tray and see if there are any options for turning it off, if its the elantech I think you can turn off the click, the symantic one, or Dell one you might be able to set it to hold for 5minutes or something crazy like that so that it wont click unless you hold it for 5minutes which you will never do.....try it see what happens
4th, to change the wallpaper..while you are in the desktop, right click and click on personalize..follow the prompts..wont work on Win 7 starter edition
5th, a 6cell battery is available if you feel you will need it, the 3cell will probably last anywhere from 2-2 1/2hrs
6th, not sure what size hard drive you have, but if you have 160gb, you do have a good amount of space..it depends on what you mean by load it up