For the last 15 months or so, I've been using the fantastic and FREE Mint.com service to track our personal finances, budgets, and most recently our 401(k)s, auto loans, mortgages, and even our home's value.
I am a data lover and previously kept a detailed spreadsheet that had 20-30 entries that I had to manually update whenever we got a bank statement, credit card statement, etc.
Here is what mint.com does for you: You link your bank accounts, credit cards, retirement accounts, real estate, etc in your account and every night mint downloads the transactions and categorizes them. In the beginning, you need to identify the correct category for each entry, but after that - mint begins to recognize where you spend and automatically assigns the category (and does a great job of it too.) You get access to detailed spending and savings reports, graphs, charts and net worth figures updated to the minute.
One of the ways mint makes money is over in their "Ways To Save" tab. Here, they analyze your account and offer you better programs based on your current situation. For example, right now I have an offer for a zero percent credit card from Discover and a Virgin Atlantic "Black" American Express card with a $200 sign up bonus.
We have been using the great budgeting feature for our grocery bills. Our new years resolution was to reduce extra spending here and since mint downloads all of our transactions (we use debit for almost all purchases), we can see immediately where we are in spending vs budget.
Give Mint.com a try, you'll love it.