For your needs, the MacBook Air 11 will work fine for writing papers, Internet research, etc. However, depending on what type of Keynote/Powerpoint presentations you will be doing, the small screen size may feel uncomfortable.
I layout all my Keynote presentations on my main Mac Pro computer, and then do refinements of those presentations on my MBA. Same goes for longer articles I write.
The key to using the MBA is setting a Dropbox account and working between the Air and a larger remote access computer.
If your projects are not that complex, however, the MBA will serve you well, no matter which model you get. I guarantee you that this will not be the last Mac laptop you buy, so dont worry about buying the base model. Most Mac users end up buying faster models of Macs eventually. I hold on to my Mac hardware for about 5 years before I upgrade.
I layout all my Keynote presentations on my main Mac Pro computer, and then do refinements of those presentations on my MBA. Same goes for longer articles I write.
The key to using the MBA is setting a Dropbox account and working between the Air and a larger remote access computer.
If your projects are not that complex, however, the MBA will serve you well, no matter which model you get. I guarantee you that this will not be the last Mac laptop you buy, so dont worry about buying the base model. Most Mac users end up buying faster models of Macs eventually. I hold on to my Mac hardware for about 5 years before I upgrade.