Is that a floorstanding 27U rack? On wheels, or solidly mounted to the theater structure?
Drawers and any equipment with controls you'll want to adjust, disc trays, etc. should go at a height that is convenient for use. On a 4-foot floorstanding rack, that will be near the top of rack. Nobody wants to bend down to push eject and load a disc...
Is that a rackmount UPS? (5-6U for 1500VA? Should be able to get that in a 2U package.) Typically the UPS(es) will be the heaviest thing in the rack, and will go all the way at the bottom for tipping resistance, especially if the rack is on wheels. Other heavier items should also go down low for the same reason (though it looks like most of your equipment should be relatively light). Having open space at the bottom is not recommended at all, as the rack will be top-heavy and prone to tipping.
Your AVR will need ventilation space above it - stacking a disc player on top of the AVR is no good at all.
I have a fan panel (middle atlantic) that draws air through the AVR and out the back of the rack, and 2U above / 1U below the AVR for airflow. If the top of your rack is vented, you might consider putting the AVR at the very top so that you don't have to waste valuable rack space on ventilation.
Rackmount gear is generally front intake, rear exhaust - this applies to your behringer amp.
Considering all of this, the UPS, power conditioner, and Behringer could probably go at the very bottom (especially if you don't have to touch the controls on the amp normally) - float the AVR, disc player, and drawer to the top for convenience. The shelf of misc sources (cable box etc) could go anywhere, assuming you don't have to operate controls on those devices.
Here is a diagram of my rack that might help spur some more questions - happy to help. The UPSes/battery packs and QNAP are the heaviest gear. Drawers, Oppo, and AVR are at comfortable access height. Xbox is a little high but it's hardly used. Amps are intentionally up high to deter accidental adjustment.