I always thought, like Zed (maybe this is a Canadian intepretation, perhaps it's how things are listed on menus?), that the highball glasses were the short heavy-bottomed glasses, until I got a book about mixing drinks, which indicates a highball glass is the tall sort (also called a Collins glass, which someone referred to above). The short, heavy-bottomed glasses are called rocks glasses. I still get the names mixed up because I called the short ones "highballs" for so long.

I like my morning orange juice in a rocks glass - my all-time favourite OJ glass was a rocks glass. Alas, like all great glasses, it broke, and now I use a less-satisfying rocks glass.