i would just go with cfls, those incandescent flood lights suck. too much heat for the small amount of light output. cfls are just as cheap and do a much better job imo. and as I.R. stated above, even the smaller hps bulbs, although they will fit into a standard socket, they must have the appropriate ballast.

this is another excellent lighting site, i have ordered here numerous times without problem
http://www.plantlightinghydroponics.com/