Here's my herp room, 14'x8', I have WAY too much empty space. Luckily, my snakes are outgrowing their 15qt tubs, and need to be upgraded so I'll have to order a few more 32qt. racks.
I use the oil filled heater on a Ranco to keep the room a constant 84F. For lighting I have two dome lights suspended in the room set on timers.