I happened to hear a TV weatherman say that wind strength is not just a question of how close together isobars are. He claimed that long, straight line, isobars indicated stronger wind too (as compared to a similar spacing but curved). This morning’s 0600Z MSLP chart has a good example with isobars in a fairly straight line from west of Portugal to Finland.
I can’t think of any met theory to support this claim. Has anyone noticed a correlation between wind strength and straightness of isobars?
I would have thought that the charts are drawn up to reflect the forecast weather, and that the weather was not influenced by the way the charts had been drawn! 
From the Handbook of Aviation Meterology Met.O.630 AP3340 dated 1960:
Limitations of the geostrophic rule
The geostrophic wind is a precise measure of the true wind only when a balance is struck between the pressure gradient and the Coriolis force. This is an exacting condition, and is strictly fulfilled only with straight, parallel isobars. If the isobars are curved or if the pressure distribution is changing with time then additional forces are involved which may make the geostrophic formula inapplicable.
I happen to be at the Met office in Exeter on a course at the moment and we covered this very fact today.
If I remember the presenter correctly the geostrophic winds are slowed slightly by the curvature around a low to give a slightly slower gradient wind. A very quick google on the WWW brings up the following page which explains how the centrifugal force comes into play and has to be balanced out, resulting in the wind speed slowing.
http://ww2010.atmos.uiuc.edu/(Gh)/guides/mtr/fw/grad.rxml
As the wind rotates around a region of high pressure the forces work together resulting in an increase in wind velocity.
