Yet another topic of debate: Intact Opening or Extra Capture?

There's yet another doubt in my mind. Is it better to be too conscious about openings and resist a temptation to capture a piece that would affect your opening structure, or just take it anyways as a temptation and gain a piece, as most players do? 

For example, just imagine this situation: 

This is not from a game or anything but a self-made example.

• Is it better for White to take the Bishop that was purposefully moved to f5 to weaken White's centre control? Maybe White could have thought of regaining the control later. Will that be possible? 
• Or is it better for White to play calm and just ignore capturing the Bishop? Will that be more useful in the middlegame? 

A good hint on this topic would help. Thanks! 

black is clearly in a better position whatever white does...so white should capture the piece

A piece is an enormous advantage. If you can win an opponent's piece at the cost of a structural disadvantage and some loss of central control, it's still very much worth it. However, in this case black's last move should have been Qh4+, and after you take the bishop that's still what he should play, but after white moves his king, he is likely already winning.

You must be joking! An extra piece is a huge advantage, even through Black gets a check or two, but a piece is an piece; White must be better!

Snap it off with no regrets whatsoever!

You are a piece up for nothing!

Who cares that it shatters your structure. Stuff like doubled pawns is "tiebreak" criteria as Dan Heisman calls it. Factors such as material advantage is generally way above any positional criteria or stuff like "oh I can't castle...".

Exceptions arise when it is some sacrifice to get a winning attack but this is definately not the case here.

I say take all the material you can. Don't let your opponent psyche you out of it...If you can't find some legitamate reason not to take it, then take it.