Speaker Combo
You first have to consider a few things. 1. How much do you want to spend? 2. Do you want to keep the same brands all the way through? 3. Do you want more bass or more high end sound? 4. Your driving habits, windows open, etc.
I have Infinity Kappa Uniplane speakers in my 93. I love them, but they are very expensive almost $700 per pair. However, you could get Pioneer speakers and a head unit for under $400. The head unit is the most important part of the system. It can power your speakers, as well as powering an external amplifier. I would recommend the DEH-P5200. It only costs about $250 and it looks really good at night.
The speaker choice is up to you, but stick with the name brands: Infinity, Pioneer, MB Quartz, Kenwood.
If you have any questions, then post them under my system post. You can look at my system, which isn't on a college buget, but it may give you some ideas. Good Luck!