If you're getting a compressor, get a decent one - cheap ones don't look very reliable.
I just got this one on ebay - VIAIR 75P Portable Compressor Kit 00075 - compact and robust; I like it; have tested it, hopefully will never have to use it.
I figure my approach to a flat tire would be a) try pumping up tire with compressor (maybe a slow leak) b) put on mini spare, maybe with roadside assistance if I have cell service - a real pain if it's a front tire, as then you're supposed to put a full size tire from back onto front and the mini spare on back c) if in a really bad spot, use fix-a-flat + air compressor d) start walking (skiing?) to help!.