End-user laptop firewall available?

[Richard Owlett <rowlett@cloud85.net>]

I chose phrasing of subject line to emphasize some peculiarities 
of my needs.

End-user emphasizes:
  - I am *NOT* an expert
  - my system is never intended to be a "server"

Laptop indicates:
  - small standalone system intended to operate primarily 
*WITHOUT* any networking

When connected to internet it will be:
  - primarily for browsing, email, Usenet
  - occasionally used for downloading small files using HTTP 
*NOT* (never?) FTP

The "fly in ointment" will be:
   The typical internet connection will be with a USB dial-up modem.
   When I desire to browse complex website or download a large 
set of files,
     I will carry it to a local library and use a WiFi connection.

A couple months of reading has left me confused as to a suitable 
firewall.

Any help/direction appreciated.