Here's a look at what a team made up of the best players judged by fWAR over the last three seasons might look like. For all the spots except the bench, it's a strictly objective measure of who has the highest fWAR by a player with significant time at each position. I have to use a little subjectivity to put together a sensible bench. The second best catcher by fWAR is obvious, McCutchen as the fourth outfielder is obvious, but then I tried to round it out with super-utility man Zobrist, the second best shortstop in Reyes, and a big bat who can also play the field in Beltre. This leaves off some guys with higher fWAR (most notably Dustin Pedroia and his 17.4 fWAR) just because they don't fit into what I view as the most typical bench construction.
Of course Mike Trout and Miguel Cabrera are tied in fWAR over the last three seasons. Trout barely played in 2011 though, so...yeah.
There is surprisingly little change from the 2010-12 team. Among the position players, Trout is the only new name. He took Josh Hamilton's spot. In the starting rotation, Clayton Kershaw replacing Roy Halladay was the only change. There's a little more turnover in the bullpen: Greg Holland, Koji Uehara, Kenley Jansen, and Aroldis Chapman are in, while Sean Marshall, Matt Belisle, Matt Thornton, and Rafael Betancourt are out.