For my push mowers, I use whatever 5w30 or 10w30 synthetic I have left from my 5-qt. jugs. (PP, Mobil 1, SynPower, Super Tech FS, etc.) Push mowers aren't fussy creatures.
The lawn tractor fill is Mobil 3 10w30.
The snow thrower is running Mobil 1 0w30. (I've used 5w30 previously, trying something new this year).