Of course, the critical down side to SSD vs HDD is cost. Standard HDD is somewhere in the $.10-20/GB range. SSD is closer to $2.00/GB. That's the part that clinches it for me. If you can afford even a modest SSD drive to install Star Wars on it will save you a lot of loading time.
For installing the game: go to SWTOR.COM and click on Login (I don't know if the sites the same in Europe, but on the US site it's top right). Once you've logged in normally click on "My Account" (again, top right). This should take you to the Account Management page. On the right hand side is a column with various links. Click on Games (Download) and this should take you to a page with a link to download the game client, matching the version you purchased. If you have CDs you can just install from those directly and then run the updates.