(My niece bought her own house, and she's recently had a lot of renovations done - the right way )

I don't think you can ever go really wrong with the usual off-white, painted, walls and carpeting that can stand up to a lot of abuse; but too many property-owners try to do some work themselves that they either aren't skilled enough to do or else because they think they can slap something up and save some money.

Some people overestimate their handyman skills, and it shows.

When something like new counters or new bathroom fixtures aren't done right, besides being a pain in the neck for tenants that kind of thing makes bigger problems (as far as damage and fixing go) in the long run.

I also agree that with rented accomodation it is not best to use expensive materiels when "kitting out" the house. I rent a house out, and rather than paper the walls we painted throughout in neutral colours. We chose hardwearing carpets and just put curtains at the windows, again in neutral colours.
This then allowed the tenants to change the colour schemes to suit their tastes.