Ever really stuck and need a logo – all your client can give you is some useless over-compressed jpg that's 100x100px!
Well, if it's a company of any reasonable size that we're talking about, check out Brands of the World. This is an excellent site that has a large collection of vector based logos from Adidas to Mentos, and Napster to Zagreb Casino.
Now, I've never worked for a company large enough that their logo is on this site, but I have worked for some companies that have. Brands of the World saved me a chunk of time and, if you're a designer, I recommend you bookmark it now.
By the way: take note that the search function is at the bottom of the page – a bit of a design flaw, but forgiveable.