Drop, Baby, drop
Lately for me on my uke it has been "Drop, Baby, drop" the chords and picking are easy or "Island in the Sun" by Weezer. Songs that are repetitive in chords and easy to remember, I find myself playing often. Good question it makes you think. Although, if you like to perform and sing for others I was told it is good to master at least 3 songs that you can play off the cuff.
Mahalo~Sonseeker30