Nice video here YouTube - GPS (http://www.youtube.com/watch?v=4Fl718QO_xQ)

Now (unless your system is somehow configured differently from mine) you should see a window of about 850 width, and 'HQ' highlighted at the bottom.

What I don't get is that HQ is (or was?) always 640x360.

What's going on here..?

Must be your config - my window is exactly 640x360 in good ole' IE7.

It depends on your cookie. The "HQ" button toggles back and forth between HQ (960x480) and standard mode (640x360). If you're in standard mode, this link should force it to display in HQ: http://www.youtube.com/watch?v=4Fl718QO_xQ&fmt=18*

I guess I don't understand the original question, other than to say that YouTube, like all other websites, is subject to constant updating and tweaking.