If my team left my city, I'd be furious. Of course you have the right to change teams!

Pick whomever you like. Base it on style of play, personalities, uniforms, fan base, whatever.

Just try to be original about it. I would guess most non-Ram fans in your area are Chiefs or Bears fans so try to avoid those teams if you can help it. Nothing against them but if you don't live in the actual city they play in, don't follow the herd.