Really follow @koanhead and try the live environment, it will run slower than an actual install, but you can easily see what will work and what might not.
For things like torrent downloads you’ll have plenty of applications in Ubuntu. Word doesn’t exist for Ubuntu, there is an application that can make it work, but it’s not very well integrated, and you still have to pay for Word. Ubuntu comes with OpenOffice, which is more than likely capable enough for you. However, if you already have large complex Word documents (i.e. that end in .doc or .docx), they might not be displayed perfectly in OpenOffice. To ease the transition, you can already install OpenOffice for Windows and see if it works for you – it’s free or charge.
Also, be sure that, if you have installed Ubuntu, be sure to check the manual that was installed with it, as it should guide you around most basic tasks.
Have fun! :)