Right now all my built-ups are boxed. It's been a war zone here for the last half a year now and the dust is sumthin' terrible...
I'm going to build my own display case, but if you can find a decent one for cheap, that's a good option. Especially if you can make it somewhat dust-proof.
A buddy of mine uses what you mentioned, some plain 'ole shelves, and they do the trick nicely.
Whatever you can afford basically, that's why my case is a long way off at the moment. My grandiose carpentry plans would result in an equally grandiose financing plan!
Fade to Black...