How do you plan on carrying this gun? These are popular as pocket carry guns and in this case right away there is a disadvantage to your model 36 - exposed hammer that can easily snag on clothing and foul your draw. The popular newer guns alleviate this problem: the LCR and the 442/642 have fully concealed hammers, while the 649 has a shrouded hammer that won't snag but can still be cocked to fire single-action (it is ugly as sin, imho, but strangely lovable).
Personally I went with the Ruger. The LCR is extremely light and some j-frames can match it but they are significantly more expensive. The LCR has a fantastic DAO trigger. Ruger customer service is one of the best, while S&W has some horror stories; ditto for overall quality. Honestly, the j-frames are really great guns but I think the LCR is better for an everyday carry gun.
By the way, the .38spl LCR is the lightest version; the .357mag one is a bit heavier, which might help with recoil; 9mm requires moon clips; .22LR has right rounds; .22mag and .327mag have six, if I'm not mistaken. You definitely have a lot of choices with either the Smiths or the Rugers.
Anyways, try them both and go from there. If you want to come down to Harvard some time, you're welcome to try my LCR .38
edit: I picked up my LCR for $350 barely used from FS. I carry it daily in dress slacks in the financial district in Boston and no one's ever noticed. Great little gun.