I hate spread sheets, I can't use Excel to save my life!!.. But I can't live w/out my contact management software (ACT). I have a database for marketing and database with current clients. I keep EVERY thing there; such as, contracts, financial policies, and every communication with the client/staff.
I like Flash and PowerPoint for marketing and presentations
I use Quickbooks for financial management/taxes, not so much for invoicing anymore as paypal is just much easier.
And for the kicker.. I get made fun of for this but it has saved my butt a million times or more. I love notebooks. I have a notebook for every client, I have a notebook for my family, I have a notebook for holiday shopping, etc. I have an entire closet full of notebooks. There is always a few notebooks right here at my desk. No PHI of course, it's meant just to take notes as I'm making a call to a carrier or I'm calling DMV, or a doctor for one of my family, etc. I guess you can say I still love my paper and always will