If you're looking for financial tools to run on a Linux system, it'll be worth your time to have a look at this article on TechRepublic.  Note that not all of the tools are open source.

1. GnuCash (I personally use this)
2. KMyMoney
3. Moneydance
4. Appgen MyBooks
5. NolaPro
6. Linux Business Accounting Systems BasicBooks
7. Quasar Accounting
8. SQL-Ledger
9. Rapid Graphing Software for Technical Analysis of Stocks and Commodities
10. Crossover Office

TechRepublic