My suggestion is to not rush into this. Spend some time planning and give yourself a budget for kitting out the room well.
If you're able to use a CAD program take the time to draw up the room and the key tools you need to provide room for. If you're not good with CAD then do the same thing but with pencil and paper. Draw up the room and details and then make little paper cutouts of the bench, storage and other key features and play with them to achieve the best overall arrangement.
I'm not a big fan of pegboard anymore since it takes up a LOT of room on the wall for very little actual storage. Instead I've come to believe in the joys of old second hand kitchen cabinetry and counter tops. For the lowers stick with mainly drawer units for storage of tools. And a pantry cabinet or two gives you lots of storage for other things. Small tools can be arrayed in a shallow drawer by using things like cutlery separators and other tricks. Only the very most commonly used tools can benefit from some sort of bench top tool caddy. But make it portable so you can move it and use it instead of taking the stuff out and simply lay it on the bench to clutter the place and get lost.
Storing the actual model components is never an easy task. A rack of some form on the wall is pretty much a must. Or if the ceiling has exposed joists you can set up storage for some of the stuff up in the space between the joists so it doesn't hang down very far. That's using room that can't be used for anything else and is a big help for keeping the floors and walls clear.
At the bench plan on a foot well or two to allow sitting on a stool while doing some tasks. But make the bench/counter top the proper height for working while standing.
For bigger models and other bigger projects a work island is often the better way to go. And a 12x18 room has the space for that sort of setup. The island can be put together from some kitchen style lowers so there's even more storage for all manner of stuff.
And don't forget about power. Wire EVERYTHING so you have outlets where ever you might even possibly need them. And lighting. You can't have too much lighting. Make sure it is positioned so that you're not casting any shadows on your working area.
Since I had my CAD open already I did this quick two minute sketch to perhaps give you an idea or two. I have NO IDEA what major items you have that also need to go into this room so this is a REAL quicky that illustrates what I'm saying about using kitchen cabinetry in the shop.
It's not shown but I'd suggest a wood working vise for the island. They are nice for this because the vise and jaw sits on the edge so the top of the jaw is only flush with the surface. And give yourself some holes for bench dogs in the island work top for doing wood working items or simply for holding stuff with the vise or by using a bench dog.
And for metal working a second vise over on the wall mounted counter at some point where it has room to work but it's reasonably out of the way. Putting it over by the drill press makes a lot of sense actually.
The grey is upper shelves and the white lines are the counter top with cabinets under. At one point on each side of the "L" I'd leave out one cabinet so you have a foot well to use with a stool. The tan coloured things are 7 foot tall floor to ceiling pantry closets that give you LOTS of storage for all manner of things.
And one thing you can NEVER have too much of in a shop is storage ability...