Personally, I'm not a fan of any wheel over 17" on an old truck. They look too flashy, and big chrome wheels are a huge turn off. No offense to anyone who likes 'em though!
I have a set of American Racing Outlaw II's on my F250, too bad they're 8 lug, because I would rock them out on my K10. I also have a set of American Racing AR-23's for the F250. They look really good on lifted K10's. Stock 15" rally wheels look killer when mounted on 35" tires on a truck that's lifted. As a matter of fact, I just completed my set of Rally wheels so now all I have to do is find tires for it
I'll post pics of my wheels on the F*** later today! (Too dark to get any pics right now)