I don't like the default appearance of Opera, but with about 30 seconds of playing with it, it looks fine.
Here are my suggested modifications:
1. Add rewind back foward next reload and home to the bar right underneath the file edit view ext line.
2. Remove all of the things to the left of where you type in the address bar. (basically you are moving them up to the top like in IE).
3. Reduce the icon size to 40%.
I think thats all I do but there might be another bar in there I completely remove. Basically going from top to bottom its 'menu bar', 'the bar with rewind back forward next reload home', 'the bar with tabs', 'address bar', web page.
Oh and one other thing, I think Opera 7.54 allows popups by default. To change that go to Tools -> Quick Preferences -> Block unwanted popups.
I'm using the Opera 8 beta now, so I have kind forgotton a bit on how to get Opera 7.54 looking good.
btw- the beta has been rock solid for me, and also lets you use gmail, unlike 7.54.