I use the Persil non-bio as it gives the least irritation problems. Seems to work OK at 40 for most stuff.
Fabric conditioners are out with my skin, not sure what they're supposed to achieve anyway and they stink..
Ecover products are a disaster, especially their washing up liquid which makes my skin go bright red and burn, once with a visit to A&E.
I agree with the regime some others are following. 40 degrees most of the time, 60 for towels, bedding and cotton handkerchiefs, and a 90 degree wash once a month or so to sterilise the machine. I'm another who uses this for cleaning cloths (not the oily bike ones though) and also the ubiquitous yellow dusters. It's still 90 degrees so will kill all the bugs just as well.