Obviously being able to chill a beer down to proper pitching temps (or even lower by a few degrees) is a must, but I don't believe that time is that essential. I have an old copper immersion chiller I have been using since I started brewing (about 11 years ago). On average it will take me about 1 hr to get the wort down to low 60's F on a 5 gallon batch. Lagers will take me up to 1.5 hrs sometimes. Yes, this is a lot of water usage and I occasionally use a pre-chiller to drop the last 20 deg. or so and the time does eat into the brew day, but the beers have not suffered. I brew in my garage and chill with the lid off for the entire time. I have no sanitation issues and even very hoppy IPA's come out great. I liken this my slow chilling period to those who add a hop stand into their brew days adding an extra 20-40 minutes post boil to their day.
Most definitely when I upgrade my brew equipment a better chiller will be in order, but until then the beers have been coming out pretty well and place well in comps. So, I guess the moral of the story is to not be concerned with extra time it may take to chill your beer to proper pitching temps provided you get it under 140F fairly quickly (i.e. 10-15 min) to help reduce any additional DMS formation that might reoccur after the boil.
Cheers to my crappy IC!!