Do yourself a favor and do a search or two here on XCs (and/or AWD) as Volvos AWD system has not exactly been troublefree or cheap to repair if and when things happen. One very important consideration is that the car MUST always have 4 good, identical tires at all times or else a costly part fails.
Unless you really need AWD, I'd highly suggest buying a 2WD wagon instead as that's a far better car which will give you less problems and be less costly to own. Although the AWDs are turbo, the added drag of driving all wheels slows the car down noticeably when compared to a 2WD turbo V70. Gas mileage with AWDs is also worse.
As for ground clearance, the XCs are higher BUT the car isn't like an SUV, it's not anything that you'ld take off roading on rough logging trails so the clearance doesn't really matter as it won't help you when driving on streets everyday.
Get a good 2WD 850 or V70 wagon instead, you'll be happier in the long run.