MiLF (Most Likely First) Interface
It seems to me that having the numeric keypad as the "front page" on a touch screen smartphone is just a hang-over from fixed keypad phones. I personally wouldn't use the keypad to dial anyone other than the emergency services, I don't even know my own mobile number never mind anyone else's.
If you pick up your phone and nothing is happening (no incoming call or message, no alarm) then you are most likely going to do one of three things: make a call, send an SMS or open one of your favourite applications. So the front page should have big buttons marked "Call" and "SMS" a small number of icons to start your favourite apps and a button to open the main menu for when you want to do something out of the ordinary.
If you hit the "Call" or "SMS" buttons you should be presented with a list of the people you are most likely trying to call or text and then one more button to open your whole contacts list. You could also include a button to take you to a conventional keypad. The "most likely" list would be made up of the top 4 or 5 phones you call or text most often (gathered from call/sms history) plus the person who called/messaged you last if they are not in the top 4. On pressing on a contact number an optional confirmation screen would say "Call - Contact_Name on Number" with big "tick" and "cross" buttons.
This means that for most of your calls you will tap "Call->Contact's number->Yes" rather than "Menu->Phonebook->(lots of scrolling)->Contact->Number->Call->Yes"