why avoid the arcade? needless to say to find the original consoles in stores would be hard. I really never liked the new slim consoles, due to the heat they generate, i really liked the last batch of 360 consoles in early to mid 2010, they generated the least amount of heat.
personally I would find a used 360 that was manufactured around 2010, pointless to buy new right now since the next gens are coming up.