Top tip - best source of real world mileage: Browse
http://www.Fuelly.com. You can see what people are actually getting, not what the DOT says you'll get.
Kudy, just how big a hatch do you really need? There are a lot of smaller wagons out there. Not many will hold a 4x8, but they will hold a lot of ther things.
Older cars2003-2007 Mazda wagon was only available in V6, so not much better mileage than an equal sized CUV, and similar to the Subaru Legacy with the 2.5L engine. I owned an '04 Mazda 6 sedan with the V6. I got 19mpg city and 27mpg highway. My AC was stuck to always be on, most other people got a few mpg better.
Mazda3 hatch gets good mileage, is fun to drive, and has reasonable space. I'm a fan of them.
If you need taller, the Mazda 5 is an option.
A friend has an '05 Forrester - back when it was a tall wagon with off road abilities rather than a CUV. Seems to be a good car.
The Vibe/Matrix is a great car that gets good mileage and is very reliable (don't let the Pontiac name scare you off, it was assembled on the exact same line, using the exact same parts as the Matrix, but depreciated more because it was a GM - it's a good used buy).
The Honda fit holds an obscene amount of stuff for such a small car with the seats folded down and more than 30mpg in real world driving (again, look at fuelly). The Honda Element doesn't get great mileage, but does hold a lot of stuff.
Kia Spectra5 were good cars. The Spectra5 has a huge cargo capacity with the rear seats folded. The Spectra5 was based on the Elentra, so holds up pretty well (I'd avoid any Kia pre 2007 though). As mentioned, the Hyundai Elentra Touring is a solid car (based on the European i30 I think, it isn't actually an Elantra).
Thinking of european based cars sold here, the Saturn Astra is actually an Opel Astra. Pretty reliable by all accounts. We only got the 140hp engine (good mpg). I test drove a base model five door and it was actually a hoot to drive with a very German feel. I actually liked it better than the same year Golf.
The Jetta Wagon TDI was mentioned - they are expensive to maintain at the dealer, but independant shops aren't that bad. Family friends had (may be still driving?) a '95 passat diesel ang have no complaints (they haven't had it at the dealership since the warranty expired god knows how long ago).
Newer CarsI have a newer Impreza (WRX) wagon, and it holds a lot (not a 4x8 mind you, but enough most of the time). I purchased mine for a number of reasons, the low and inexpensive maintenance, and excellent long term reliability were definitely things that swayed me to the Scuby (well, that is what my right-foot tells my brain anyways).
The 2008+ Imprezas are actually based on the Legacy platform, so they aren't that small. The 2012 is costly (being brand new) but gets much better mileage than the older ones.
Being a Subaru owner, I've got a natural dislike for the Mitsubishi Lancer (If you don't know, it's kind of a Mustang vs Camaro thing). But the sport-back Lancer isn't a terrible car (actually it is a fine car).
New Focus 5 door is light years ahead of the old Focus.
The Mazda3 with "skyActive" engine option gets 40+ mpg.
1) early 90's Honda Accord Wagon
2) late 80's Corolla or Civic Wagon
3) mid-90's Ford Escort wagon
...
People in the NW love their Subarus, but they seem unnecessarily complex if you don't need 4x4.
Personally, I'd stay away from all of those. While they may be cheaper to maintain per maintenance, safey and emission standards have improved considerably since then. When I'm on my motorcycle I'd take getting stuck being a new Escalade over any of those - the fumes of an 80s civic are noxious! Overall reliability is much higher today (better assembly, and much better materials). It may cost you twice as much per maintenance, but you'll have far fewer.
Realistically, cars today are miles better than they were even ten years ago. Even a cheap Korean car maintained properly will last a really long time. And the fuel mileage of some of these small (but not tiny) cars is really incredible.
I will agree that unless you have reason to want the AWD you are paying a lot in fuel costs for nothing. They are pretty solid, so repairs aren't often, but the complexity means that the potential for expensive repairs is definitely there. If you're looking for a cost efective car, FWD (with good snow tires) is good enough.