Can anyone recommend a place to buy an office chair that'll be good and durable but not stupidly expensive? Or even a particular chair you've got that you really like? My partner spends a lot of time at his computer and he appears to put all of his weight onto one side of the chair, because his previous (large, sturdy looking) office chair basically collapsed to one side and the whole back and side came off. He's currently using a little folding chair which doesn't look very comfortable (and is also now listing slightly drunkenly to one side!) so I thought I might get him a new one for Christmas, but there seems to be a LOT out there. All recommendations gratefully received!