Keep in mind the limitations on this deduction, both over and under 6,000 lbs have deduction value, but not full purchase price.
http://www.section179.org/section_179_vehicle_deductions.html
For passenger vehicles, trucks, and vans (not meeting the guidelines below), that are used more than 50% in a qualified business use, the total deduction for depreciation including both the Section 179 expense deduction as well as Bonus Depreciation is limited to $11,060 for cars and $11,160 for trucks and vans.
Certain vehicles (with a gross vehicle weight rating above 6,000 lbs but no more than 14,000 lbs) qualify for expensing up to $25,000 if the vehicle is financed and placed in service prior to December 31 and meet other conditions.
I believe this is precisely what the recent legislation changed, from $25,000 to $500,000. A small business owner could buy several (large) vehicles, up to a total value of $500,000 and deduct them all. Mostly, those who have already done it sometime during 2014 will be the ones who benefit, although I'm sure some large orders have been placed during these last few days.