@nusquam, then instead of bikes, jetbikes then? HB+Multimelta may be worth it? About the deathlock, the only way that I can see to spam them is with the Void Reavers special rule and giving them to terminators. But a unit of of five is too much due lethal exposure. Two of them will be the max I could give (to a termie or a marauder squad). My main opponents are necrons, 'nids, blood angels and the occasional tau and eldar and IG.
@Ishagu, that depends on the theme and the way you want to field your army.