I'm quite fond of the Code Writer app, and just discovered it has indent guides available in the settings. One thing that struck me about it, though, is that there's no highlighting of your current indent guide. I find it really helpful when I'm skimming through sections of a file, to have an indicator of what level I'm at.
For reference, see the second image at http://indentguide.codeplex.com/ (first under Indent Guides) and see how the guide for the current line is highlighted with a soft glow.
I personally prefer a stronger indicator, and configured mine to be something obvious without looking straight at it, but it's nice to at least have something there that makes it easy to ensure you haven't overshot your target when scrolling around.
Ideally the highlight would be on the first indent guide to the left of the cursor, but the last guide on the current line would work for v1 on the feature if it makes things any easier.