Chrome for full auto or use in harsh environments...
Otherwise (eg for normal day at the range use)...
In order of accuracy:
SS:
Chrome-Moly
Chrome-Lined
In order of durability
Chrome-Lined (not by much over CM, though)
Chrome-Moly
SS
Chrome-moly is the 'compromise' BBL, and also the least expensive... More durable than SS, more accurate than chrome-lined... Note that in terms of durability for non-competition use, we're talking upwards of 30,000 rounds for chrome-moly, a tad more for chrome-lined...
Reliability is a non-issue, I have a 100% chrome-plating free rifle that has perfect reliability, I've known people with all 3 bbl types that have had stellar or less than stellar results, evenly distributed across manufacturers...
Supposedly chrome-lined guns clean up better... Can't comment on that one, though...