Gnucash is the next generation of money manager created from a merger of
X-Accountant and GnoMoney.

Its features include:

* Ability to import Quicken files ( a must ) 
* Reports, Graphs, and all of those goodies that you find in Quicken. 
* Gnome compliant ( if that is the correct way to put it ) 
* Separate the GUI from the actual "account/transaction engine" 
* Multiple accounts ( Check, Credit, Cash, Mutual Funds, etc.. ) 

See http://www.gnucash.org/ for more information.