Web Browser

Firefox is an award winning next generation browser from mozilla.org.
www.mozilla.org/products/firefox/

DOS Emulation

DOSEMU stands for DOS Emulation, and is a linux application that enables the Linux OS to run many DOS programs - including some DPMI apps.
www.dosemu.org

Personal & Small Business Financial Accounting

GnuCash has many features that support basic accounting needs for individuals and families, starting with an easy-to-use checkbook-register-style layout, and supporting things like bank statement reconciliation, stock/fund portfolios and numerous reports/graphs. But GnuCash development doesn't stand still, and the newest versions add support for small business accounting. Also has support to import Quicken .QIF files.
www.gnucash.org

HTML & CSS Editor

Nvu is a complete Web Authoring System for Linux Desktop users to rival programs like FrontPage and Dreamweaver.
nvu.com