Hi,
If I recall, by the math, its something like 256 users....or is it 133..... In real world, its probably more like 20, but that is obviously a total guess on my part.....
Here I have about 20 IP reservations using a mix of wired and wireless, including a couple printers (one ethernet and one using shareport). I have had as many as 5 or 6 pc's using simultaneous connections over wireless and one wired with no slowdown from my perspective. I have looked at the logs during these times and there are a ton of various internet connections (can't count them all)....
I will say that I have been migrating most of my wireless devices to .11N to the extent possible. Hopefully apple will open the alleged .11N in the iPod Touch 3G instead of .11G as is current. The two laptops here both got nice little PC card adapters to .11N off ebay for about $10 each.....
I don't know what the DIR-655's "crush point" (my word, not DLink's) is, but its gotta be way better than my old routers......
YMMV as they say.....