I use gallon jugs of drinking water for top-off, or preboiled tap water but either way I put them in the freezer for about 3 hours before I expect to pitch. They are almost always just at or above freezing when I'm ready for them, usually with a little slush in them. While my boil pot is cooling in the sink (water bath), I'll shake-aerate and pour my near-freezing top off water into the fermenter then dump my partially cooled wort in on top of it, then any additional top-off water needed to reach volume or target gravity. I'm almost always at 70-72 degrees and ready to pitch within 10-15 minutes of flame-out with this method, and I think it's more sanitary than ice cubes.