I agree with George that a double X stand, or a table style stand, should be OK for the YPG-625.

jeffc, if you're leaning toward a YPG-525, I think you might want to look at a DGX-500. It's basically a 525 with MIDI IN/OUT, a disk drive, and fewer Live! Cool! etc, sounds. I've seen them go new on eBay, with warranty, for a little over $400 incl. S&H. That's a hell of a good deal!
http://music.yamaha.com/products/main.html?productId=43

Rick