If you plan to view a lot of graphics with Netscape, or download large files from FTP sites, you will benefit greatly if you purchase a high speed modem. A 28.8Kbps is nice and necessary for some of the newer multimedia technology. If you only plan to use text based tools for the foreseeable future, you may be able to postpone a modem purchase. This is somewhat subjective, you need to try it yourself to see. For those considering a purchase, external modems are desirable because you can use them with any system, and it is easy to see the LED's.
Internal modems work fine too and reduce desktop clutter.
We use 33.6 Kbps V.34 modems in the PPP modem pool .