Do you guys wash your hair in cold water or just rinse with cold water at the end?  The rest of the time, do you use hot, medium or luke-warm water?

I've been washing in luke-warm water and rinsing in cold.  Then I wrap my hair in a towel and let myself enjoy a hot shower, without it touching my hair.  Is this ok?

I use warm water to wash and initially rinse, then finish off with a cool rinse.  The cool water will close the scalp and help prevent oil production.  

I wash & rinse warm, then luke-warm to cool finishing rinse.

Typically, I use coldest water that I can stand on any given day. Cool-ish to air temperature during the winter, because I'm a sissy,  :P  and cold during the summer.

Personally, I have no idea how you manage finishing your shower with a towel on your head lol but more power to ya if t works!  ;)  So long as hot water doesn't touch your hair, you should be fine.

I take baths instead of showers, so I have trouble using really cold water.  In general, I run the bath a little warmer than the coldest I can stand (it cools down a little by the time I get to my hair).  If I am washing only my hair in the sink I use cold water.

When I'm taking a shower for my all over  body I use hot water but for my hair only I use luke-warm for washing, and the coolest that I can stand.

No, using the coldest water is wayyyyyyyy ok!  I'm not sure if you've heard this saying from a famous female actress.  She is the most beautiful actresses in the world!!  Her name is Jane Seymour, and her hair beauty secret to healthy shiny hair is that she washes her hair in cold water.  No warm or hot water at all.  She washes it in the coldest water that she can stand.  She says that the cold water closes up the hair follicles and hair shaft, and it calms down the  frizzies, and gives your hair a  beautfil healthy shine.