A S & W 442.
Product: Model 442
It has an enclosed hammer so that it can be pulled from a bag without snagging; it will not be affected by lint. It can be tossed in almost any bag without a holster and still be safe. It is light weight and will carry well. It shoots 38's (and +P 38s) a proven round.
Or go to the Scandium verison which shoots .358 and weighs 11.4 ounces (but is very expensive).