Here is some advice on purchasing a computer to last through your career at Iowa State University.
Get what you want. Today there is little difference between a Macintosh or Windows computer. Get whatever you are comfortable with. You can dual boot Windows and Mac OS
on your Macintosh. You can also run virtualization software
on top of Windows or Mac OS
Make sure that it has enough RAM and hard disk space. Today's applications are using more RAM that ever before; make sure that it has at least 4 GB
of RAM. Anything more than that is just fine also. (Caveat: 32-bit operating systems can only address 4GB RAM. Upgrade it to 64-bit if you have more than 4GB RAM.) You will also want enough hard drive space to store your files.
Video cards are great, but they're only extremely important if you are considering doing graphics work or games.
Be sure to purchase enough warranty. A standard college career is at least 4 years. If you don't want to replace your computer before you graduate, make sure that your warranty will cover you.
Other than these 4 points, there is little advice to give. We recommend purchasing through a computer retailer, as they tend to have better service.