BillShrink.com lets you compare credit cards based on all your specifics (miles vs. cash, where you shop the most, etc) and tells you what the best card is for your specific habits.
MOD EDIT Looks like billshrink.com is shut down. From their site:
Dear BillShrink customer,
As you may have heard, BillShrink.com was shut down on July 31, 2013.
While we’re sad to say goodbye, we hope we’ve been able to help you be
better informed and save some money along the way! The good news is
that much of the innovative award-winning BillShrink technology will
still be available via our StatementRewards platform (made available
to customers by our partnering financial institutions). Moreover, we
expect to re-launch a new money-saving service in the future. To see
more of what we’re up to, visit Truaxis.com.
We have deleted your personal information as of July 31. We will
retain your email address only to announce a preview of the new tool.
If you do not want us to retain your email address, you can opt out in
the form below. This opt out feature will be available until September
31, 2013. If you have already opted out previously, you do not need to
opt out again. If you have any further questions, contact us at
Thanks, The BillShrink/Truaxis Team