Vitali is probably your best bet if you want to see Valuev KOed. Wlad hits harder than both Vitali and Haye but with his cautious style I wouldn't put any money on the line that he could actually stop Valuev inside the distance.
ok, i may have trouble explaining this in english. what I wanted to say is they have heavy hands but an impact of crisp-high velocity punch is greater therfore bigger. so that's why I believe haye hits harder or maybe it's even better I put it this way- his punches have more devastating impact.