Shade
I agree with Gregory on the choice of Barbara Moore's book. I do think that the arrangement of the cards has a profound effect on the reading. Cards in a vertical line suggest something very different from cards in a horizontal line for example.
As to you question about whether it is useful if the arrangement thing isn't your thing I say yes as she discusses
1. How the spreads you use should match your personal tarot philosophy
2. How to makes changes to spreads so they are more useful to you
3. When to go with specialized spreads vs general ones.
I gush about that book in this thread:
http://tarotforum.net/showthread.php?t=174643&highlight=barbara+moore
As to you question about whether it is useful if the arrangement thing isn't your thing I say yes as she discusses
1. How the spreads you use should match your personal tarot philosophy
2. How to makes changes to spreads so they are more useful to you
3. When to go with specialized spreads vs general ones.
I gush about that book in this thread:
http://tarotforum.net/showthread.php?t=174643&highlight=barbara+moore