Brewing 6 US gallon batches has increased my need for more bottles by several orders of magnitude. I just got a large shipment of 1 ltr PET bottles in from Mr. Beer to help with that problem.
Because home brew beer needs to carbonate and age for weeks after bottling you need to have a 'pipeline' of beer so that a new batch of brew is conditioning while an older batch is being drunk. I figure I really need to have three 5 or 6 gallon batches of beer in bottles and in the pipeline at any one time. That is a lot of bottles.
I suspect that eventually I will get tired of bottling and will move into putting my brew into kegs but I'm not there yet, so it's bottles for now.