Well thats a tough one but the ones that are currently stuffed into my garage are..

1918 Speedster
1922 Model T Touring Car
1929 Model A Roadster Pickup
1935 Flathead V8 Chemical Spill Truck
1996 Explorer Sport 5 Spd. (Only to make 4x4 it up driveway)
1999 Dodge Avenger ES V6 (work car)
2002 Lincoln LS V8 (weekend car)
2005 SRT6 Crossfire (when I want to show off)
2008 Ram 2500 6.7L, 6 Speed
But I would easily change a few for...

Duesenberg SJ
1940 Lincoln V12
Grandfathers old SL500
55' T Bird, Olive Green
1932 Packard Twin Six (V12)
Any new AMG Benz

the list goes on and on and now i'm sitting here with a hardon and drowling