Personally I think that Spotlight style search launchers are the best way to launch applications. If the search launcher is designed halfway well, with learning about which applications you use most often it only takes a few keypresses to bring up the applications you need.
Of course with touch devices it is probably more convenient to swipe to the application icon you want and touch it, but on the PC I find it much easier to click the search icon, type the app name and press enter.
If you can remember the name of the application without prompting.
I'll frequently have to troll through my /Applications directory looking for something that does X that I know I installed ages ago and will recognise when I see it.
It's important to have multiple useful ways to get to your applications. My unprompted recall, in general, is quite weak, but someone else might have vision issues that makes distinguishing icons apart difficult. For this kind of basic functionality, I think that having several high-quality approaches is best.
A good reason to include meta info about applications, so it can be pulled up after name matches.
Personally, I've almost quit using the Windows start menu. I hit win-key and start typing. Utterly pathetically slow and inaccurate compared to using something like QuickSilver or Alfred, but I can still get places much more quickly than using a mouse when I'm programming.
Of course with touch devices it is probably more convenient to swipe to the application icon you want and touch it, but on the PC I find it much easier to click the search icon, type the app name and press enter.