Damn, I thought the mighty mouse would be a good option, considering that it is symmetrical in design.
Not that you want to go with a wired one, but some early mighty mouse wireless mice have problems wiht right click and need to be fixed (do a search on it) and, personally, I found the wired mighty mouse to be work better than the wired variety.
The OP probably has, I get the impression it's the physical action of the "right-click" that annoys them.
You're going to need to look at some of the lower-priced versions of a lot of mouses because there are a few symmetrical ones around. It sucks that they don't make left-handed versions of the cool mouses.
Yeah the Mighty Mouse is a bit of a pain if you rely on secondary clicking a lot. I rarely use secondary click in OS X so I don't mind it, but recently I've been using the Mighty Mouse to play World of Warcraft which really needs two mouse buttons. Surprisingly, though, I haven't really had much problem with secondary click there.
Anyway, Microsoft has a symmetric mouse designed by S+arck link, and most of Kensington's mice seem to be symmetrical. I seem to remember someone making a mouse in style with Apple's own mice, but with two separate buttons and an old fashioned scroll wheel. I can't find it, though.
Have carried out a search as requested and it does seem that the 'right click' is a bit dodgy.
So i have been on to Apple and they are sending out a replacement, so i will see how that goes if i still dont like it then it will be getting replaced with the one suggested by MacRumorUser which i like the look of alot.
Consider the Razer ProSolutions 1.6 mouse (made for Mac and ermm....windblows). It goes really well with my white Macbook and is a neutral design which is why I chose it. I'm also left-handed and I find it a pain to use my right hand. The Razer is a top quality mouse at a good price. Gee, I sound like a commercial .