I think the bus drivers in local traffic seem to have come up with the same solution. They usually drive a few meters past the bus stop, so most of the people have to walk beside the bus forming a line naturally before stepping in. Always makes you wonder why more people don't stand after the stop at the point where the bus door will be. Guess that's people for you.

I'd say that 400W would be enough for the uber-highend. I think high quality 300W PSU would be just about enough for powerful gaming machine.