Thanks for responding. She will be flying out of Chicago (either Midway or OHare) and as far as what she will be spending, it won't be tens of thousands of dollars, just about one trip per month (all over the US).

Free flights/miles would be nice to cash in on...but it sounds like we may get our best 'bang for our buck' with the introductory offers on these cards? (Especially because some of them have pretty high annual fees after the first year...or so I've been noticing.)