This is a short, but immensely powerful article. At 84 MMbpd, world oil demand has barely declined. Any breif world economic recovery could send us right back into the supply/demand crunch saw last year. Even China growing at 8% in 2009 would put a strain on world supply. This is especially true when coupled with declining production in historic production areas (think Mexico).
At historic prices the world seemed to max out at about 88 MMbpd of supply. Two or three more years with any considerable economic growth should really test world production capabilities.
http://seekingalpha.com/article/149642-looks-like-oil-production-already-peaked