My all time starters.

Off the top of my head (outfielders by position, although I don't think I'd change if considering three OF):

C Berra
1B Gehrig
2B Hornsby
SS Rodriguez
3B Schmidt
LF Bonds
CF Mantle
RF Ruth

I'm pretty comfortable with these players.  I considered Bench and Piazza for catcher and Ted Williams for left field.

A pitcher causes more hesitation.  Candidates: Johnson, Johnson, Grove, Koufax, Gibson, Seaver, Clemens.  Choosing four starters is easier than selecting one pitcher for one game.  Let's go with:

Four starters chronologically: Walter Johnson, Lefty Grove, Tom Seaver, Randy Johnson.  Nice spread in years.

5th starter: Roger Clemens.