YC doesn't have desks as such. We have long dinner tables custom designed by our architect Kate Courteau that some amount of work also gets done at (<a href="http://www.vinodnarayan.com/wp-content/uploads/2011/05/y-combinator.jpg" rel="nofollow">http://www.vinodnarayan.com/wp-content/uploads/2011/05/y-com...</a>), and a few conference tables that are all different.
I don't think my exact model is made anymore, but it's extremely similar to this: <a href="http://www.amazon.com/White-Frosted-Glass-Steel-Fighter/dp/B003VOJOT0" rel="nofollow">http://www.amazon.com/White-Frosted-Glass-Steel-Fighter/dp/B...</a><p>I've had it for about 5 years now. I like the size of it and it's surprisingly sturdy, but I'm not overly fond of the glass top, because it's so hard to keep clean.
This isn't a pic of my actual desk (pulled from Google Images) but its the exact same desk I have, minus the drawer (was too lazy to take a pic): <a href="http://farm5.staticflickr.com/4118/5221683438_8716ac1be8_z.jpg" rel="nofollow">http://farm5.staticflickr.com/4118/5221683438_8716ac1be8_z.j...</a><p>Been using it for the last 6 years. Works great.
I don't use a desk. I work on the sofa, on a chaise lounge in the sunroom, on a folding chair on the patio, sometimes in bed. With a laptop, on my lap. If I'm tired of sitting, I have a freestanding shelving unit in the sunroom that's the right height to put the laptop on top of while standing.
This is my favorite desk:<p><a href="http://www.hardwoodfurniture.com/sitting-standing-computer-desk.htm" rel="nofollow">http://www.hardwoodfurniture.com/sitting-standing-computer-d...</a>
I personally use a desk called 'Bivi' <a href="http://myturnstone.com/settings/private-office-2/" rel="nofollow">http://myturnstone.com/settings/private-office-2/</a> As far as YC, perhaps someone else will know.