Quickbooks is the way to go for the financial part of it. My church went to that in Jan 2010 and I absolutely love it. One nice thing about Quickbooks is that they have proadvisors listed on their website according to location and you can find one in your area. I used mine frequently the first month, to make sure I was understanding things.
I strongly urge you
NOT 
to get Membership Plus 11 - It is a disaster of a program and has more problems than it is worth.
I am currently looking at church management systems myself and have a couple that I am investigating myself and haven't decided which one yet. I am looking at Power Church and Church Helpmate 2010.
If you go to ecfa.org/TopicDisplay.aspx?PageName=SoftwareVendors it has a good article on what to look of in Church Management systems. There is also a link at the bottom of the page of a comparison chart of all the various programs out there and what they can and can't do. It is a very through document.
http://www.ecfa.org/Documents/SoftwareVendorChart_List_2009.pdf - OK I decided to include the comparison chart link here for you also. Happy Hunting.