I prefer standard tunings, but once in awhile I tune my short scale down to D standard because I like the way it sounds. For practical purposes I'll just grab the 5 string since most anything I play below E can go all the way down to B.
There are a handful of songs I play that go down to Bb, and for that the 7 string is nice. But I'd also like to try a 6 string tuned to low A standard, it might just give me everything I want.
Never cared for drop tunings, or retuning in general. I realize they're helpful for a lot of songs in certain genres, but what little of those I play I play on the 5 string.