IE8 was pretty good. I actually found myself using it. IE9, and a couple others as well, seem all be moving in an incredibly counter-intuitive direction; They're redesigning the UIs to make use of screen real estate, shrinking the tool-bars, hiding buttons, and burying options. With the size of modern monitors, why is this helpful? It's just making all the tools and options I use constantly harder to find and use, and they wonder why so many people resist updating?
My personal favorite was IE 6 as far as ease of customization and set up to use the minimal amount of browser real estate. I could get everything I needed on a single line. Ever since that release the minimum has been 2 lines.
I even went to using Maxthon for a long time as it had the same set up as IE 6 did (single line customizable).
Now I guess I just don't care as much as I can find much more to whine about besides how lame a browser is