For a complete off-grid setup, you're going to spend some money alright.
It is more efficient to run 12V loads directly, if you have 12V compatible things to run. But there will be lots of things that are just not convenient or exhorbidently expensive in 12V form. For example CFL lighting for mains voltage is practically free. For 12V, CFLs are hugely expensive where they are available at all. If lighting is a significant part of your requirement, use an inverter to power fluorescent lighting.
Another downside to 12V loads is that you might find you want to run the DC charge and inverter circuits at 24V or 36V, and then 12V loads are just not compatible at all.
I would really be leery of running a fridge from off-grid electricity. My fridge is LPG. They cost a bit, but they work great and no electricity at all is needed.
Definitely go with flooded lead acid batteries. Gel and AGM are great and all, but for a large capacity stationary application, they are not cost effective. Also do not get automotive cranking batteries, as they cannot handle deep discharge and do not have the Ah capacity of a "traction" battery. Cranking batteries will not last.