[09W]

...we all know most people with the baby diesel are lucky to see an average over 20 mpg...

I don't think that's remotely true (barring towing). Via a year of observation of numerous forums, it seems like most are getting better than their rating.

8500 miles to date and I'm averaging high 23s, low 24s with basically no highway time, in the most congested state in the U.S.. Best so far was when I had 1 week of commuting via the Parkway (about 30 mins 1-way total) and my best hit 26.4. (My combination is rated 22/26). This motor gets solidly over 20 with ease.

 

[09W]

I've been driving diesels since '06- in my state diesel was cheaper than gas right up until about 2 years before that, when it inverted. All along diesel ran between roughly 25 cents and 75 cents more /gal. Currently tho it's about $1.75 more ($4.25 vs. $6). Up until the diesel price jump last week, getting 6 or 7 MPG better than gas -even with diesel being .75 more /gal- you were ahead, money-wise. Now a gas truck is cheaper to run than a diesel.

Hope the price spread shrinks ASAP. I'd never sell my Duramax because of fuel price tho.