Applications that do not use the internet seem unafffected, such as the current version of Adobe Photoshop Elements, or the software I use to burn CD's and DVD's. It is mostly surfing. I use FF 3 with 10 addons. Things like WOT, Noscript, adblock and filterset G, download status bar, cookie culler and Foxmarks. Startup time for FF was about 30 seconds, down now to about 10. I think that is mostly due to FF checking for updates and all the addons too. While using the browser for Gmail, Yahoo mail, and many sites that I frequent regularly that I am very accustomed to the load times consume at least half the wall clock time. Boot time is reduced also but I cant really say how much. It used to take so long that I had learned to anticipate when I was going to use the PC then go away and come back later when I was ready to start. Waiting for reboots when I install software or things like Windows Update were painful. It's at least half of what it used to be, maybe more.
I don't really have the expertise to say why this is, if I have to guess it would be memory constraints. I have two systems, both Dells (different models though) and fairly old with 2GHz processors, slower FSB and memory speeds than we see in new machines this year. But the kids PC, which also had both Blink and WFW running did not seem to be nearly as affected. They run mostly the same software but they use IE. I mostly use IE on that machine too since I'm doing windows updates or some other admin type maint on that box and it's about all I do there. There is a noticable improvement on the kids box but not nearly as dramatic. The difference that I can see is the kids PC has 2GB of memory where mine is 768MB, so I assume that memory plays a large part in the problems I experienced on my box.