For me, I reference both frequencies for the log, in the format (my TX freq)/(my RX freq) - sorta like how repeater frequencies are usually shown - along with the satellite used. This is useful to know what frequencies you used for the contact, and could be important for satellites with uplinks and/or downlinks in more than one band. For example, AO-51... uplinks are normally on 2m and/or 1.2 GHz FM or SSB, but have also been on 10m in the past; downlinks are on 70cm or 2.4 GHz FM. At the moment, you can work AO-51 with a 2m FM transmitter and listen to the downlink on either 435.300 or 2401.200 MHz FM (+/- for Doppler).
In my electronic satellite log (spreadsheet), I also keep details of my radios and antennas used. There are times where I have separate RX and TX radios, and some cases where the RX and TX antennas are not the same. I may remember what I used as my station at different times and know what frequencies were used on each satellite, but I'm OK with keeping more information in my log for future reference.
Good luck and 73!
Patrick WD9EWK/VA7EWK http://www.wd9ewk.net/