Practical

For minivans, some Toyota Siennas have AWD and are probably the most spacious option.

For mid-sized SUV's, the Honda Pilot is probably the most common vehicle that will fit your criteria. They all seat 7 and I think most have awd. You can almost get a new base awd Pilot for your budget.

The Toyota Highlander fills the same niche as the Pilot and all have awd and 7-8 passenger capacity. You actually could get a new one for your budget, although it would come with the less powerful 4 cylinder engine option.

The Mazda CX-9 is also 7 passenger, is powerful, and will probably have the best driving feel to it.

In my opinion, these are the "smart money" options given a $20k-30k budget; awd and 7 passengers. These have the best combination of fuel economy, reliability and depreciation in the segment.

Mwcten has made a few good suggestions. It's hard to get more specific without knowing more about your priorities and perhaps your initial reactions to his suggestions. Any?

There's also the Explorer or the Durango. But do you really need AWD? If you're getting AWD just for snow, it's really not necessary unless you're driving on roads that aren't maintained. Winter tires make the biggest difference.

The Explorer is a decent vehicle, and it has good enough room even in the 3rd row. I don't really like how it feels inside, though. Not very good visibility, especially looking back, and the doors are quite far away from you making it hard to tell where you're placing the car when you park for example.

I haven't had any experience with the Durango, but I've heard good things about it.