No garage is what makes it tricky. Can you park on a drive/offroad somewhere out of the way where you could put it under a car cover?
Next, it kinda depends what use you want out of it. Is it just for road use, country lanes and weekend trips kind of thing, or more of a trackday toy? That might dictate how practical you want it to be. An R400 would be awesome on track, but not exactly ideal for a weekend away.
Personally, as a weekend toy I would forget practicality as far as you can.
I think I'd probably be looking at Elise/Exige/VX220, maybe BMW Z4 or Boxster.
Again personally, if it was a classic at that budget it'd be a 911.
