I think most of us acknowledge the value of getting on base, but I am not sure to what degree. There are plenty of people out there who might not see the true value (I am speaking to you Jimmy Rollins). Many people who subscribe to old school mentalities often can't bring themselves to new concepts (or even new old concepts). It is important that we understand the basics behind OBP
A baseball team gets 27 outs to score as many runs as they can. The key concept here is the word "outs". This is not a zero sum game. It's not like a work week where if you take off on Monday you only have 4 more work days left in the week. While this seems simple, it is often hard to grasp in concept. This basically means that each team can have 27 to infinity batters hit in each game. Obviously, the close to infinity you get, the more likely you are to win the game (or, at least tie it).
So, what is the real value in getting on base? The value lies within it's two main results.
a) Putting another player in position to score
b) Putting another player in position to hit
The first part is the easiest to see and is the most obvious result from getting on base. A player gets a hit or walks, they are now on and can be driven home. That, in itself, is a pretty inportant event. They have gone fro mthe phase of attempting to hit the ball to the phase of no longer needing to hit, but trying to score. And when you are fortunate to move from the trying to hit phase to the trying to score phase, you are not using up one of the team's 27 outs.
We have all heard the criticism of Bobby Abreu and how he tries to walk in important situations. What many of these critics appear to ignore is that we aren't just skipping over Abreu's turn in the lineup. He has added value by getting on base, putting him in position to try to score AND allowing another player on the team a chance to hit. The goal is to have as many plate appearances in a game as possible. The more appearances a team has, the more likely they are to score runs. The correlation between plate appearances and runs scored is EXTRMELY close to 1.
OBP is very undervalued in the statistic OPS. OBP has much more value than SLG, especially at high league rates of OBP. As OBP approaches 1.000 the value of SLG drops to 0. Who needs a homerun when you know every batter is going to get on base. While OPS, itself, doesn't mean anything, it has fostered the concept of OBP and SLG being weighted equally in our minds. This is highly unfair to high OBP players like Bobby Abreu.
An even more rudimentary concept than scoring runs or getting on bases is maximizing team plate appearances. The more often a player gets on base, the more often other players can hit.
Bobby Abreu type player: .450 OBP (this year)
Chase Utley type player: .350 OBP (this year)
Jimmy Rollins type player: .310 OBP (this year)
27 outs in a game.
Team of Bobby Abreus: 27*1.45 = 39.15 PAs
Team of Chase Utleys: 27*1.35 = 36.45 PAs
Team of Jimmy Rollins: 27*1.31 = 35.37 PAs
The team of Bobby Abreus has over 2.5 more plate appearances in a game than the Chase Utleys and 3.5 more than the Jimmy Rollinses. Over a week, that 26.46 more PAs than the JRs and over the year 612.36 more PAs. Ignoring the fact that you are putting players in a spot to score (very beneficial), you are giving other players on your team more chances to score and to get on base as well.
There is nothing more important in baseball than to get on base.