The base V6 is a great choice for all the reasons you mentioned, however I would strongly consider the Tech package (SYNC, power seat, fog lights, auto-dim mirror) unless you have plans to go aftermarket later on, as it's very reasonably priced and helps ease the daily grind of commuting.
18K OTD will be pretty tough, the prices you see advertised are usually inclusive of all possible cash incentives (even ones you may not be eligible for, like the Competitive Lease Conquest $1,000 rebate). I think Ford is putting about $3,000 on the hood today, so if you take a starting point of $21,000 (which is below invoice and doesn't include destination), subtract the $3,000 in incentives, and add in TTL you'd be looking at around $19,500 OTD, so $18k would require the dealer to sell the car at around $2,000 under invoice.
Currently doing online negotiations before I set out to the dealers. The general market price out the door is in fact $19-19.5k. I am currently trying to press to go under $19k and will hopefully hear back soon.
I am really excited that the wheels are finally turning and will soon be a proper member! Trying my best to keep emotions out of negotiations and ensure I get the best value for my money (ie. 22 year old college kid still going to school and planning to pay for the purchase myself) so every penny counts/I have always been about getting most out of your money.
I'll report back soon and hopefully have pictures by tonight