On May 18th of last year, Bush signed two executive orders regulating energy policy. One, on accelerating the permitting process for energy related projects, was cribbed directly (word-for-word, in places) from a proposal drafted by the American Gas Association, an energy lobbying group. The other, on energy supply and distribution regulations, "closely tracked" a request from the American Petroleum Institute. The Gas Association was particularly pleased, since they had originally drafted their proposal as suggestions for a bill to be given to the Senate. Public debate is so tedious and slow.
(The original drafts of these orders, on lobbyist letterhead, were among the papers of Cheney's energy task force that the White House was trying to conceal. Strictly on principle, of course).
So, it wasn't just Enron. While Enron did get favors --- like choosing both the White House policy on access to local power grids and the FERC regulators who would implement those policies --- they weren't special favors. The White House would roll over for anybody.