I think it depends on the band. If the studio recorded album went over well (gold, platinum), then a live album is probably a good idea. But live albums never sound as good as studio recorded. :/
In my opinion, live albums are usually more than just quick bucks. The artist or group that releases them generally is doing it to please their fans. I'm not saying it isn't done to make up for inactivity, because that does happen a lot, but it's also almost a way of saying "Hey, we're still here, we sound good live, and we might go on tour." (Which may or may not be a conflict of opinion between the artist and the label.)
Live albums tend not to sell that well when compared to studio albums. But there are still very successful live recordings from bands such as The Who and KISS.
I don't think the difference is so much the artist, but more so the song. Some songs just sound great live and echoing, while others are better fit for a sound-padded room.
But overall I do favor studio over live. Better yet, I'd go for the deluxe editions, which often include live bonus recordings, or even the occasional DVD releases, which feature a fuller experience.