I've been drooling over Laura Foster Nicholson's ribbons for quite a while but they're rather pricey and I don't have a specific project in mind. So far I have been resisting the temptation to order them just to have them to look at. For now I just look at the photos on line for ribbon like this one (click for a big view):
I could use the ribbon on cosmetic bag such as they did here, although mine won't wouldn't be as large (check out the dimensions...snicker).
Another source for fun ribbons is trimfabric. I ordered from this on-line source a few years ago and had fairly good response from them. They've since revamped their website but I think they still deal in mostly mill-end textiles, so their stock changes. I do think their multiple-view pictures of fabric, buttons, and trim are some of the best for an online store. Here's one of their vintage ribbons (I don't know if it's really vintage or just a vintage look):
And finally, mjtrim has a wide selection of ribbons, lace, buttons, and other baubles to adorn your projects.