The Start screen is annoying because of the difficulty in finding application shortcuts for infrequently used programs
You mean when you can't remember the name of the application you want to start? Because otherwise you just have to search by name.. which it does automatically as soon as you start typing... But if I can't remember the name I tend to not find stuff in the startmenu either. In the startmenu it often also place the program under a folder with the company name... so if you don't know what the company is called then it can be really hard finding stuff in the startmenu.
In both Win7 and Win8 I pin the stuff I always use to the taskbar. Then I usually create a Toolbar to the old quicklaunch directory (home\AppData\Roaming\Microsoft\Internet Explorer\Quick Launch) and add all the infrequently used programs to that... I have something like 50-60 programs in that toolbar. But I hardly ever use it since it most often is easier to just press windows-key, type name, and press enter.
Personally I think the startmenu was a bad solution from the beginning. I didn't like it in Win95 and I don't like it in Win7. Maybe that's why I don't care. I can agree that the startscreen isn't much better... but I don't think it is any worse. (I like the concept of live tiles though... That I don't have to start a program to see information about it...)
The search by typing the name is good though... but that hasn't anything to do with either the startmenu or the startscreen. They are just the UIs used to show the result in. You have the exact same functionality in BSD/Linux/unix terminal or the spotlight in OSX... but there the result is shown in the shell or in finder respectively.
On another note, I've just had the dreaded PBSOD (Pale Blue Screen of Death) on Windows 8. On Windows 7 I never once had the BSOD. Hope it's something that will be fixed soon.
Mmm.. I Have had a couple of those on Win7 because of memory faults. They disappeared when I got new memory modules. On Win 8 I only had one. That time it was the DisplayLink Beta driver that did something nasty. But since they released a full version it hasn't happened.