Continuing the the 'Linux on the Desktop' discussion, I often heard people ask about a heavy duty, industry standard financial software. Frankly, I use GnuCash. Granted it's not really designed for a large business (ie accounting firm), but it suits me just fine. In fact, the package has made reliance upon Quicken a distant memory.
*Aside* - GnuCash has finally released a beta product based on Gtk2 libs, now that's newsworthy ;)
Now there is talk about another commercial product, TurboCash opening their source code. While I think it's great, I'm not sure if it's exactly newsworthy.
There are always firms who secretly desire to get access to more open source developers, so announcements like these garners the attention that they need.
Eventually, someone will probably reverse engineer their product anyway.
freshmeat.net: Category Reviews - Financial Software for Linux

I just started using GnuCash and mostly like it, including the double entry accounting system.
The one thing that I'm missing from Quicken is the Budget feature. I understand that there is a long sordid history of the GnuCash developers arguing about the design for budgeting. I hope that the new Gtk2 version is robust and has a nice budgeting feature.
I found:
LB: The Little Budget tool - http://www.teuton.org/~bugler/lb/
but have yet to try it yet.
Are you using anything for budgeting?
Actually, I've not used any special budgeting tool for GnuCash. I basically use my P-cash utility on my Treo, and transfer the data to the PC. Unfortunately, there is no conduit sync utility for PDA and gnucash. I'm sure it's coming tho.