Another vote for Subaru, as far as I can tell, a Subie would totally meet your needs, and come in way under budget, and way over what you are looking to get in gas milage.
I wouldn't recommend a WRX though- they are FUN, but are also very limited in cargo capacity/utility.
I've owned a crapload of high-milage Subarus, many well-past 200,000 miles, a few made it over 300,000 before getting retired. All of the high milage ones met a lot of abuse and kept on ticking.
I would rate Subaru reliability up with Toyota and Honda- really really really good.
The only reliability issues I have had or heard of:
1. Almost all of my Subaru's over 100,000 miles have had the alternator go out, and then the part-shop replacements seem to die every two-three years. Its a 45 minute job to replace (seriously simple because the engine Is oriented the right way and the alternator is on top). I make sure I buy a replacement alternator with a lifetime warranty, and in the past, I have swapped the lifetime warranty alternator from used Subie to used Subie to make sure I don't have to buy another one.
2. Normally Aspirated (non-turbo) 2.5L Subaru's from 1996 to about 2005 are notorious for blowing head gaskets. They went through like 20 revisions of the head gasket before sucking it up and finally redesigning the head. In general, cars that make it to 100,000 miles without head gasket issues tend to go the rest of their life just fine, but cars that pop headgaskets tend to do them repeatedly, even when they are replaced the "right" way with milling the head square. I've bought several Subaru's from the generations with problems, and haven't been bitten yet, but I have passed on a few. If I see the headgasket material on head doesn't match the other head, I'll probably pass. You can test the antifreeze for hydrocarbons- if there is gasoline in the coolant, the car has a bad headgasket- pass. The 2.2 models did not have this issue, and ALL of the turbo models of all displacements do not have this issue- they use a different head design.
I keep buying Subarus because I can't ever seem to find anything on the used market with the same value. $15 will buy you a LOT of Subaru, especially compared to many of the other cars on your list.
For what you listed above, a Subaru Outback would work very well, as would the Forester, only the Forester would be tighter on rear seat and cargo. Fair warning that 5 adults will be a doable tight fit, but adults and kids will be fine. I got 30 MPG highway (mountain driving) in my stickshift 1999 Outback, and have seen 1-2 mpg more in a Forester. Turbo models will scale it back to 25 mpg highway, and MANDATORY premium fuel, but are LOTS of fun.
I paid $24,900+tax for my new 2010 Forester XT.
To round out the stable, my wife purchased a 2005 Forester XS (non turbo) last Thanksgiving for $8,000.
I have previously owned:
1986 Subaru GL- Given to me for free with 230,000 miles, ran for another 50-60,000 before rear-ended and destroyed.
1988 Subaru GL- Purchased for $1,000 of insurance money, had 160,000 on the clock, given to my brother about 6 years ago, he just retired it with close to 300,000 miles.
1990 Subaru Legacy L- Purchased for $800 at 118,000 miles, ran great until a camshaft snapped in half- I've never heard of this being an issue with anybody else's car. My only "miss"
1996 Subaru Outback- Purchased for $3,800 with 130,000 something miles, killed when I drunk driver tagged it while parked on the curb.
1999 Subaru Outback- Purchased for about $5,000 with insurance proceeds, 130,000 something miles, I put about 60,000 on it and sold it when I decided I wanted a turbo model.