Here's my few cents. I have a 40 plate chiller and a CFC. I can get faster flow rates out of the plate chiller and to do a 1 pass chill I have to throttle the wort flow way back. I found that it was actually faster to recirculate the wort back into the kettle and then only go to the fermentor when the output is ~65. Doing this I can cool 11 gallons in about 10 minutes vs 20 with one pass. The CFC flow rate is to slow, even with a pump, to make recalculating an option.
Somebody mentioned using a bucket/keg to push tap water through an bunch of ice. I've tried this and it worked well until the ice ran out. I tried to chill from a boil however so maybe it would work from ~100F. I repurposed an old cornie and had a thermometer in line to see what the chiller water temp was coming out. Using tap water to knock most of the heat out with a recirculation first could make this viable for those who don't have a pump.
Most recently I built an ice water recirculator so I could brew in August. It's not really that hot here but our tap water was about 72F. I used a sump pump from Harbor Freight (sorry no link, I think there's a newer model). This worked out very well even though I didn't have that much ice. I just emptied the ice makers from our lunchroom freezers before I left work, maybe 10lbs. I prechilled with tap until about 120 and then got inpatient and switched to the ice and kept recalculating. All in all it took about 20 minutes to get 6 gallons to pitching temp. I learned a few things the first time and what I'll do next time is prechill to ~100F, switch to ice but run straight off. I have a thermometer off of my plate chiller and I was coming out well under 60F so no real need to run back into the kettle. (not that concerned about the break.
In the end, the pump worked well and I'll continue to use it for the warm months or lagers. Also, for those of you contemplating a fountain/pond/aquarium pump, Im not really sure youll get the best results do to the low flow rates. Its not that much more money to get a sump pump from Harbor Freight. They always have a 20% off one item coupon and they go on sale frequently. I think I was out the door for $30-$40. Oh, you also dont need one with a float switch but pick up a foot switch while youre there.