Recent models
From what I look at, I think that the future classics right now (and by right now, I mean the past 10 years or so) will include:
1: Maytag Neptune (first of a kind really for the American market)
2: Final round of real Maytags (always the last of anything, plus the finger faucet is the kind of feature enthusiasts would latch onto affectionately)
3: Whirlpool/Kenmore Calypso (a cool but failed attempt to adapt the front-load washing to the familiar top-load box)
4: Speed Queen (a rare and robust machine from a brand with hobbyist following)
5: High-end Shredmores (sturdy machines that are everywhere, easy to source parts from cheaper machines, familiar to most people from childhood today)
6: Final real Amanas that shared parts of Speed Queens (see #2 and 4)
7: Anything especially off the wall and rare, like Neptune TL
8: Anything from uncommon, expensive, or brands foreign to the area, Miele.
I've based this list on what people on this site appear to appreciate today (Lady Kenmores, Maytag '06, GM Frigidaires, GE Filter-Flos esp. with mini basket, and unique wash actions like Apex, Philco, and Kelvinator).