I liked this post because I do something similar, though not all in OmniFocus.

For me I keep all goals in OmniFocus, at different ‘elevations’ according to the GTD methods. But for material goods I store everything in Pinboard using tags like: to-buy gift-idea bag camera. That way I can quickly see everything and if I have some money that I want to spend on something I can filter things around and make a pick.

I’ve also found that by keeping things in Pinboard that way I don’t feel the need to buy it right away. My brain knows it is somewhere where I will not forget about it.