Prolly just red. It's earthy without looking old (brown) or icky (orange has a whole new concept to me after it being the color I associated, that I nasally "saw" from our high school's lunchroom dumpster(s(?))).
My question would be if I'd still want my veins and non-oxygenated blood to be blue. Maybe not. But I don't see my veins too often (maybe when I get older and my skin wears thin I'll care more one way or another*), and I don't see non-red blood at all. There was one time I got cut deep on my leg ('round or under the knee, IIRC), but that was just a general "really dark" color (which I guess is what "large" amounts of blood looks like when it's together and/or getting red'd). That may be an icky concept... (the color, mind, or saturation to the point of looking like congealed evil)
*This phrasing > "one way or the other"