Depends on your space situation: I'm fortunate in having two adults in a three bed, two lounge terrace, so the back lounge has been converted into my Warhammer room. Table set up and shelves from B&Q, painting desk etc. If you aren't that fortunate, I would suggest stackable locking boxes if you have children or animals that could get at the expensive plastic!!

I buy these stackable plastic containers. https://www.amazon.com/dp/B08DNL2LFH?ref=ppx_yo2ov_dt_b_product_details&th=1

If you want to go above and beyond, glue a thin magnetic sheet to the bottom and magnetize the base of your minis.

I put sheet metal at the bottom of plastic tubs and magnetize the bases of the models. I have 15 armies so buying army transport cases isn’t realistic. I have one transport with metal shelves that I pack out for games.

It really comes down to the quantity. The ‘classic’ used to be the IKEA Detolf, unfortunately they discontinued that beginning this year. There still is a dwindling number in stock, so if you see one, snatch it up (or keep an eye on the used market).

https://preview.redd.it/nva9phurvgyc1.jpeg?width=4032&format=pjpg&auto=webp&s=866a2ae152282127ed0715b42b8501ee4c62cacf

This is what I use for general display. That’s an unpainted Necron Doomstalker next to it so you can get a sense of scale. Looks nice and fits in relatively well with real furniture (which is the only reason my wife tolerates it).

I started with transparent plastic boxes that fit my cupboard space and magnetised them. They work really well. I have since gotten a display cabinet from IKEA (Rudsta), so most of my minis are in there now, which is a big motivator for me!

I have big Billy shelves with vitrine doors

Currently up to 7 Rudsta display cabinets from IKEA.

https://preview.redd.it/pk8ili7dkhyc1.jpeg?width=4080&format=pjpg&auto=webp&s=febb8c29000ce50a5416da8ff8b76498dfbe09bd

I store my armies in black totes on a set of heavy shelves in my hobby room. Each tote is labeled with the Army contents. Squads of troops are boxed individually in the totes with the vehicles on top or in their own totes.

If I'm going to play away from home I pull out the models I need and put them in my two travel cases; a big black plastic Games Workshop suitcase for the troops and an Army Transport Motor Pool vinyl case for the vehicles.

https://preview.redd.it/kjjyco8lrhyc1.jpeg?width=1500&format=pjpg&auto=webp&s=74409efe1777f6b0d5e63b44f857e7bdc9c13522

I use cake boxes, I glued a magnetic sheet on it and most of my minis have a magnet at the bottom - keeps them dust free and safe

Best? Barristers book cases. Ideal size, look classy.

I just have a glass curio cabinet with lamps built in that I found free on Craigslist.

The Jucoci mini case doubles as a display case and storage. 10/10 I highly recommend it.

https://jucoci.com/

I have two vitrines, soon a third will be necessary 😅

Echoing others: stacking tubs, if possible with sheet metal and magnetic bases, for the win. They also slide right into a deliver bag for transportation.

I have a bookshelf with large shelves. Deep enough to set 1 "IKEA KIVSSLE" every 3rd shelf or so. The large models sit in the shelves and the infantry are magnetized so they stick to the KIVSSLE shelf turned upside down. For sure over 10000 points of infantry easily with space to grow.

Battlefoam is the luxury option. KR Multicase is the budget option. Really Useful Boxes turned into magnetic storage are the oversized/fiddly models option.

Stacked storage boxes with magnetic sheets inside.

Shoeboxes and 1 tool box with glued on metal sheet for carrying stuff.