I've driven manual cars for almost thirty years. I would certainly prefer an automatic in stop-and-go traffic. I can't imagine anyone preferring otherwise. "Clutch in - shift into first - clutch out - creep a bit - clutch in - shift to neutral - clutch out" gets old real quick. Someone with weak legs would find it positively painful.
For every other situation, though, I prefer a manual. In the case of many models from Subaru, the question is more serious since only the manual transmissions are true all-wheel-drive. If you can afford a WRX, STi, Legacy GT or high-end Outback then you can get true AWD with an automatic transmission, otherwise it's only part-time, being FWD most of the time. This is the case for regular Legacys and Imprezas as well as all Foresters.
If you can't get hold of a manual car to practice on enough to get used to driving it then I think you should stick with an automatic.
If you'll be driving in snow (why else would you want a Subaru :-) it would be useful to try both the automatic and manual RS's in snow to see the difference between the two forms of four wheel drive. Either version of the WRX should be great, but as Rick Courtright wrote I'd also be wary of buying a used WRX.
Used Subarus are also a bit risky due to the problems they had with clutches, head gaskets and piston slap. New models are supposted to be better (I'm counting on it).
A used Legacy GT automatic in great shape might be a nice choice.