There is an aspect to theory that's comforting, though. I'm sure I would sleep better at night knowing that my application was using an O(1) hash table as its

There is an aspect to theory that's comforting, though. I'm sure I would sleep better at night knowing that my application was using an O(1) hash table as its map rather than an O(n) alist, even if the constant factors are higher. More hardware helps out constant factors; it doesn't do anything with quadratic algorithms.