Does the valve have to be straight when replacing a tube? I've just replaced the tube on my bike and when I pumped it the valve wasn't particularly straight as can be seen in the image below.



What I'm wondering is do I need to remove the tube and straighten it before use? I assume it wouldn't be any harm to do so but if there is nothing wrong with the way it is I'll save myself the effort. I'm going to be cycling it in the morning so I said I better ask before I do.
It should be straight out, perpendicular to the rim. Otherwise you risk damaging the tube.

When the valve stem is at an angle the valve isn't free in the hole – it is trapped by the edges of the hole where they bind the stem. The edges of the hole may cut the stem which will be moving a little bit as the tire and tube flex over bumps and the like.

There will also be an area of the tube that isn't supported by the rim (or that is stretched more than the rest of the tube) near the valve stem. That area is likely to be a weak point in the tube.

And one more thing! As pointed out in the comments below, there are conditions – such as the tire moving on the rim – that are likely to further stress the tube as it passes through the valve hole. If the valve is initially straight any angle of the valve is an immediate sign that something is happening.