At work (my employer is a networking company) my laptop speed to the internet is limited only by the wire speed of the ethernet cable, that is about 800Mbs as tested. Frankly, I cannot tell the difference between that and our 20Mbs DSL at home most of the time. I certainly do not perceive much of a difference and have never pined for faster surfing speeds at home, even give the daily contrast between the two.
As noted on the radiology example, the big difference is with large downloads, especially noticeable for OS X updates and other really large files. In those cases the difference is dramatic, but frankly they are few and far between and I am cheap.
For web surfing, where one page may have twenty or more connections required to fully load (often considerably more) latency makes the big difference in perception. Something like OpenDNS will impact the feel as well. Oh, and I do use OpenDNS at home for several years now.
