My wife has dyed her hair from beautiful blonde to a dark browny red.?

maybe you can tell her something really cheesy like.... 'i loved it when you had blonde hair' and tell her all the reasons why the blonde really had and impression on you... you could tell her that her hair looks nice so she WONT get mad.... with women you never know. Try giving her opinions on new styles and hair colors that are in. look it up on the internet and magazines if you have to

Not really; i'd leave it a bit though if i were you, and then tell her that you actually prefer her old hair colour; but if you tell her too early she will undoubtedly get mad. And ready the old stab vest for when you do tell her ;)

Tell her you don't care what colour her hair is...as you wont see it late at night in bed.

Well I don't think you should be asking us about this but I think you should just say nicely considering her feelings that you don't like it.