We're probably all snobs according to some definitions. Where I shop is guided by the quality of the food not the clientele, and I take the same attitude to where I live.
My next door neighbours are like Rose and Onslow from 'Keeping up Appearances' - I'm sure we'd have terrible trouble selling our house because their house and front garden looks like a bomb site, but I don't care - they're nice people (well she is, he's a waste of space!) I have a friend who has a nice 4 bed house on a very nice estate (although one couldn't use that word) backing onto the golf course, but I'd find it a chore because it's the sort of place that you could never leave your front lawn unmowed longer than a week in summer without getting disapproving looks, and you have to have a 4x4 or a people carrier.
DS1's nice little school is set to merge with the neighbouring one which has (whisper) council house kids attending, and the rage of indignation from some parents made me want to scream! I really don't think it will automatically lower standards if the less well off kids are allowed to mix with the better off ones!
I think instinctively I am not a snob but I dare say I have been, am and will be in some situations.