One thing you will also need is the appropriate drivers for your hardware. The motherboard chipset, video, network and sound drivers at minimum. These are all free downloads from the various manufacturer's sites, of course.
Inevitably after the install of Win 7 there will be an enormous number of MS updates to download and install as well, which will all happen automatically unless you set the windows update to just download but not install until you tell it to.
There are advantages to that particular option. One particular point that has sometimes bitten me is that MS update tends to offer some or all of the drivers mentioned above, but my experience has been that sometimes they are out-of-date, or so generic that they don't actually work too well, or don't fully exploit the hardware.
So although the MS update offers them, and downloads them, I don't choose to install them. My preference is to trust only the manufacturers sites as a source of drivers.
One final point - Win 7 comes in various flavours (not just 32-bit and 64-bit), and for certain facilities (especially joining a university workgroup) you are going to need the so-called professional version.
http://windows.microsoft.com/en-gb/windows7/products/compare#T1=tab01