Over the past few years, I've been asked a few times what I use for keeping my model paints organized. If you've read my "Painting Room" Article, you know what I've used in the past. Now that I am in my new house and I have a dedicated room, I have essentially taken the same route for my paint organization. It is sturdy, looks nice, and is relatively inexpensive to make.
I start by using strips of pine corner molding from Home Depot; you can find it near the baseboard and edging aisles. It is roughly 2 inches wide with a 1 inch lip. It runs around $1.50 per linear foot; it's not the cheapest solution around but I have yet to find something that I like better.
In the cabinet/hardware aisle, you can find 3/4 inch elbow brackets, 1/2 inch screws and bolts, and a box of drywall anchors. That's all you need to mount your shelves.
I cut my "shelves" to my desired length and marked off where I wanted to mount them on the wall. I also painted them to match my wall color (except in semi-gloss).
Each shelf was mounted onto the elbow bracket using flush screws. The underside of the elbow bracket was mounted to the wall using a drywall anchor. The shelves are very sturdy and the anchors hold them very tight up against the wall.
I placed a mounting bracket every foot or so, although you likely could get away with less. I like everything to look clean and symmetrical :) The other nice feature of these shelves is that they are wide enough to fit most any paint bottles... Vallejo, Tamiya (haven't tried large Tamiya bottles though), Testors, and Vallejo auxiliary bottles.
I am now able to keep my paints at hand and still be very organized and clean. For me, painting and modelling is much more enjoyable in an organized and clean environment. My desk is in, my cabinets are in, my painting racks are in, and my lighing is in... All I need to finish is the flooring and a my airbrush area in the garage!