Mine are all planted round my hellebores, which don't have any big leaves while the snowdrops are out, but do for the rest of the year, so there is no space to be tempted to plant something in! Works well for me, and they both like leafmould. Hardy geraniums are good companions too.
Mine are heirlooms, they all came from my mother-in-law's garden, single ones and double ones. I have never bought any, but in the last 3 or 4 years they have developed several clumps that are much taller and have larger flowers. Presumably a natural genetic variation, as it is highly unlikely that any of the few people who live within bee flight distance of me have any thing other than bog standard snowdrops, if they have any at all. Gardens aren't a big feature round here (except for me of course, but I'm clearly mad!)