I like the Ruger 22/45. I bought five of the MkII 22/45 to use as trainers.
Until last summer (2008) you could buy them for $200. I bought my last one for $250.00 at 500 Guns in Speedway.
500 Guns, Speedway, Indiana:
http://fivehundredguns.com/The new 22/45 MkIIIs retail for a little less than $300 around here.
I really love my Smith 17s and 18s, but I can no longer find them for $200. Those days are probably long gone. I still haunt pawn shops and the occasional estate sale, but can no longer find them this cheap.
17s and 18s are rising steadily. Someone I know paid $500 for a pre-18 recently.
I am also a fan of the Smith 63. I dropped $350 for a minty one last year before this model started to climb as well.
Good luck. Tell us what you chose.