Hi Chris,
I've only been collecting a few months, so my collection is tiny compared to many here. At last count I had about 90 lobby sets. These range from small 4-card sets to much larger ones like the the 25-card Barry Lyndon set. Most are 8-card. No idea how many individual cards I have now. After finding this site I ordered a supply of 100 11x14 polypropylene sleeves and archival foam board backs from Bags Unlimited. Each set goes into its own bag after inserting the precut the foam board. To date these are stored in a plastic storage tub like the ones found at Walmart or Target. My first one is full, so I need to get a second one soon, as well as more sleeves and backs.
I've been a cautious collector mostly, buying relatively inexpensive sets that go with my favorite films, many from France, Spain, and England. The more vintage high-dollar stuff will come later after I gain some experience. Keeping track of my collection has become an issue, so I need to database it somehow so I know what I have. I use Collectorz software to track about 1,000 of my blu-rays and DVDs, so I need something like it for LCs. I started collecting LCs mostly because I don't have a lot of storage space left. I've been a collector of vintage cameras for years and have more of them than I can display at any one time. Besides, my wife thinks collector = packrat...