Hey! Yep, I love this thread, too. I went off the deep end with my addiction this year and now have 90+ 1/18s. Mostly Camaros, 68-70 Chargers, and cars I loved since my childhood.
There are lots of decent retailers out there like Mint Models, Diecast Direct, Live Car Model, STM Diecast, Auto World, Diecast Models Wholesale, Diecast Depot, and many others.
I have had my best luck with eBay, especially with vintage models, hard-to-find versions, and some great deals.
Here is my Six Gens of Camaros collection in a display case (with some others):
