Imho windows/whatever boottime is relatively irrelevant, especially since normal computer spend quite a lot time doing BIOS initialization code - which obviously isn't going to be affected by a SSD drive at all.
But application startup time is relevant enough - I'm generally annoyed at anything that takes more than half a second to start. I can
forgive that for larger applications, but it still annoys me. If Visual Studio would go 1-second startup time and firefox would go down to a few hundred miliseconds, I'd be quite happy
Carol: use "start <whatever>" to do that - check "start /?" from a cmd.exe prompt, it can do lots of useful stuff.