2007-2008 TL.
3.2L J Series
(NON VCM)V6 that will get you mid 20's on the highway or better depending on how you drive. They're basically an Accord underneath with a bit bigger motor. The 5 speed AT was upgraded in that time frame and is a solid unit as opposed to the fragile glass hand grenade the previous one was. The one big thing that hurts their resale is the leather seats. They used perorated leather, so when they dry out a little they start tearing like punched paper. That and pretty much all of the dashes crack. I have a cover on mine that I'm completely happy with and I don't have to see the cracks.
Same time frame TSX's are solid cars as well. Hard to beat the K Series motor, if you can find either one that hasn't been beaten to death they, are solid cars as long as the routine stuff is taken care of.
Picture from my TL Type-S a few years back that has the bigger 3.5 engine. Drove across the top end of FL, got gas, got on the interstate and didn't stop till the kiddo had to use the restroom. My MPG calculator on that car was always pretty accurate, I'd hand calculate it, but they always matched. Three people and loaded down for a week vacation. No tricks, reset when I left the gas station, and took that pic when we got ready to leave the rest area.
As far as particuarly desirable, the TL Type-S's are getting rare, kids are wrecking them left and right and they only made them 2 years. They also tend to be a little rough and lead harder lives sometimes.
The TSX Wagon is a fairly rare beast as well if you're in to station wagons, I've always liked it and they seem to hold their value better over the sedans.