No experience, but this is what I know on the subject... There is Yellow Dog which has a very good reputation, but I've never seen it in action. Debian seems to be very popular on MACs, there are a lot of howtos on the web about the Debian installation process.
You have OS X, no need to go with Linux on the machine that the BSD core distro runs perfectly on :) Fink is a wonderful application and with all the UNIX apps out there and developers we're seeing more and more unix applications also compile properly on OS X without issues. :) Just send the developers notes about how you like their app and want to see it compile on OS X if it doesnt already.