I've had a similar experience. Taking SSRIs (Sertraline, initially 50mg/daily, now 100mg/daily) for social phobia and depression. They definitely helped increase my baseline for positive feelings (i.e., I don't spend as many days curled up in bed feeling hopeless), but it's true that it brings down other aspects of life. Decreased sexual function, loss of emotion in other areas, stuff like that.

I wonder whether serotonin is really the magic trick to increasing moods or whether it's just a stop-gap solution that works well enough for most.