Get the Honda Fit. It has a trick back seat and it is also easily removable for even more room. The Honda Fit has way more room than the Mazda2. Same size engine.
The Fit is an ugly piece of crap on the outside. The Mazda2 looks more pleasing, if not better built, on the inside.
The 2 isn't that much cheaper than the 3 and is a little down on power on paper (I've never driven one, I'm 6'4 so I don't fit in the 2). I think it's a good city car if you don't need alot of room.
id actually buy one if they made a 5spd version of it. they got another version of it called the mazda2evil i think thats going to be the version to buy when it drops