I only use 3. LOL.

1 homescreen for weather and clock, plus four shortcuts
2 homescreen music widget and four shortcuts
3 homescreen calendar widget and 4 shortcuts.

My dock slides so I have 5 shorcuts (phone, contacts, apps, sms and internet), and 10 folders. Using launcher pro.

Also if you use an alternative launcher, you can get each homescreen to be 10x10 not 4x4 icons.

 

You may want to check this out for what other people do with their homescreens
http://androidforums.com/android-themes/4425-post-your-android-desktop-139.html

 

I use five. All my app shortcuts are in folders on the front screen. Widgets occupy four other screens, and I can't find a use for the remaining two. Going to browse the desktop thread for idea...

 

I use three screens and delete the other two.

 

Never needed more than one home screen... I've simplified my SGS2...

One home screen showing a clock widget, and the battery level and weather shown in text.

And at the bottom on a barely visible dock is 5 icons; Call, Text, Apps, Browser and Camera360.

Nice and simple.

 

I've got a different phone than you but I figured I'd show you what I use 5 screens for anyways as that seems to be your main question. I know the clock/weather on the main screen and the weather on the second screen are kind of redundant but I like not having to launch the weather app to get the 5 day forecast.

 

I use Launcher Pro and use all 7 of the screens. Full screen widgets take up 5 of them (Facebook, Twitter, Calender, Bookmarks, Messaging). My main home screen only has a Beautiful Widget clock/date/weather widget customized to match my current wallpaper, and on the last screen I keep my app folders, Google search bar, and a few other widgets (My Verizon data usage, 1-tap Cache Cleaner, Where's my Car, System Panel app kill).
With so much going on, I don't go over 2 minutes for sleep mode, and if I know I won't be able to charge the phone at all for the whole day, I turn on Juice Defender.

 

I use 7... lol one as main home screen one for music and music apps one for apps one for games one for memo current events etc and one for social