I would also throw in that you should use the reverb on an FX channel, and roll off the low end (HPF) of the reverb around 250-400HZ. You don't need the 'muddy' part of the reverb cluttering your mix. I myself am not a big fan of reverb, but it is necessary most times. I find that the stereo delay in Cubase, used on an FX channel with vocals, can add space better than a reverb at times. Pan hard left and right (delay time song dependent), with one side kind of a slapback, the other side exactly double the ms of the the first. Mix 100%. Feedback set low so that is doesn't get redundant. Pull up the delay until you just hear it in the mix. Much less mud will come from that than typical reverb will.
By the way, LE 5 reverb leaves much to be desired. I am not sure of any IR (impulse/response) type reverbs that are free, but I would advise looking for one, or purchasing one. I can't remember the last time I even bothered using the Roomworks reverb. It just is not very pleasing IMO.