I'm level 66 atm and haven't prestiged. I don't really intend to prestige for the same reason as Bateman said, I don't need the little icon to know I'm good. To me it's just a headache prestiging(sp?), Having the weapons and everything I have earned to continue raising my K/D ratio and increase my score means more to me than the little icon.
My K/D ratio is about 1.62 I think and it was around 1.10 a few weeks ago. I love my ACR w/ greande launcher, I haul arse with it. The killstreaks I have been toyign with are Harriers, Pavelow, AC 130. Those net me a fairly high number of kills each match. I also go with Sentry Gun, Pave low, AC 130, that beast got me a 36 - 1 killstreak which was awesome. I consistently have high scoring matches, in the 20's or higher. So after I had a run of a few 25 or greater killstreaks I thought I'd give the nuke a go. So now my killstreaks are harriers, pavelow and nuke.
I am yet to get the nuke but I'm close, I keep getting taken out just before I'm about to get it GRRR!