Jennifer Lopez, Ben Affleck Go Christmas Tree Shopping with Kids

Jennifer Lopez and Ben Affleck have a large staff handling their day-to-day, but one chore is strictly hands on -- going shoppin' for an XMAS tree!

Ben, Jen and their brood hit up a vacant lot in Santa Monica Saturday ... littered with Douglas and other firs.

So many to choose from! The fam got downright pensive and they inspected various options. It's an important one for sure ... it's their first tree as a married couple.

They spent quite a bit of time at the lot, eventually settling on what looked like a balsam fir -- a huge one -- that they tied to their SUV as they beat it.

Everyone seemed to have a voice in the choice ... including Max, Emme, Seraphina and Samuel. Looks like Violet was MIA.