I really like St Erth in Cornwall, there's a lovely atmosphere and on a busy Summer Saturday with passengers changing in their hundreds from main line train to branch train and vice-versa it still has some of the magic of the old Great Western - plus the semaphores add to it! I just hope they don't ruin it with this new Park & Ride scheme.
Sadly of course, it's the "only really half finished" terminus station, with so many platforms that were never and will never be built.. On the NR network, it would have to be the esteemed terminus station of London Marylebone.
Well, for general loveliness try Aigburth, Box Hill & Westhumble, Gobowen, Stoke Mandeville, Stroud. There are many others though, these are just a few off the top of my head. But please, just to assauge the sensibilities of old farts like myself, these are "stations" or "railway stations". You'll find plenty of "train stations" but they will be in America.