I'll second this. Also check out some used RAV-4 and CRV.
The Mazda3 has a rubbish back seat - especially if the passengers in both the front and the back are 6' tall. Just trust me on this one.
In this price range, I'd consider the following:
1. Scion xB. They have a fairly good back seat, and don't cost very much used. It's boring, but it's practical, reasonably compact, and doesn't cost much to run.
2. Toyota Avalon. Getting a good'un for $10k is tricky, but if you're willing to forego the leather, you can get a very good deal - low-options Avalons are much cheaper. It's basically a Lexus with a Toyota drivetrain and interior, which means it's very quiet, very comfortable, and the '05s and later have the best back seat of anything in the known universe.
3. Subaru Outback Wagon. Once again, low specs kill the resale value on these, so buying one with the smaller (4cyl.) engine and cloth seats can make for a very good price. The back seat isn't bad, the four wheel drive system is excellent, and the reliability is simply legendary.
4. Jaguar X-type. It's 100% ford, and as such, doesn't cost more to keep up than your average Volvo. It does, however, have Jaguar-spec depreciation - I've seen some with under 70k miles for $6,500.