So I normally set my screen between 20-30% to save battery, and have absolutely no problems seeing the screen brightly and clearly. However, I went golfing yesterday (sunny out) and I could hardly read my screen at all without blocking the sun and squinting. I know I could have changed the setting or used auto-brightness, but I think auto-brightness makes it too bright most of the time and drains battery, and it is kind of a hassle to go change the setting every time I go outside.
The stock HTC brightness widget only toggles between 40%, 60%, and 100%, which does not work for me. I was using Elixir to control brightness, but found it inconvenient for that particular setting with its tiny and inaccurate slider (although great for many other settings). Today I discovered the Brightness Level widget (by Curvefish) in the market. It lets you set brightness at 0%, 25%, 50%, 75%, 100%, and Auto, all with one click. You can even use the large slider at the bottom to get an even more customized level above/below one of those settings (eg. 15%, 20%, 30%, etc.). I have found 25% to be great for inside, and 75% to be great for outside. Great app, highly recommended, and free!
Hope this helps out anyone who is having the same problem I was.