I've been a fan of Stumble Upon for quite some time and really like the interface and it's probably the only social media site which I actually browse for pleasure as well as work (although Reddit has been providing some amusement too recently). Given all that, I'm currently on 999 pages liked:
Point me in the direction of some good sites and the most convincing comment gets my 1000th thumbs up! Feel free to post live links in the comments, most of them will get stumbled anyway with my 1001, 1002, 1003rd stumbles :-)
If anyone wants to friend me on SU you can find me here.
Edit: Suzi from Suzical wins my 1000th stumble for finding me somewhere to live! Thanks Suzi :-)