So my MX518's right-mouse button, although functional, has a major problem which is preventing me from using it optimally -- tapping the right-mouse button now causes it to register the click twice and holding the button makes it act as if I were tapping that no matter what I do. This calls for a new mouse.

However, I'm not really into the idea of buying another 518 -- I simply don't like having two of the same thing, tbh -- so, although another 518 is still in consideration, I'm now considering three other mice to purchase as my current 518's replacement as well: the Logitech G5, the Microsoft IE 3.0, and the Microsoft IE 1.1.

Now, I'm a guy with big hands (look at my pic in Mojo's ISC gallery to get an idea), so ergonomics is very important for me. I know for a fact that all but the 1.1 are suited for that (haven't tried the 1.1 yet, though). But based on what I've read up and having tried the G5 and 3.0, I've gathered these pros and cons for each compared to the 518:

Logitech G5 (can buy it for $59 with PriceMatch)

[+] - Tracking feels smoother than 518 (a surprise!)
[+] - Texture of the mouse feels more durable and less prone to gunk collecting on it than the 518
[+] - Weights! :D
[-] - Hard to click the mouse wheel without moving it up and/or down
[-] - Lacks a second side button (which I use for Ventrilo)

Microsoft Intellimouse 3.0

[+] - Feels better for my hand than the 518
[+/-] - Tracks damn well for an optical mouse, but no noticeable difference over the 518
[-] - Apparently, the new model has problems with its sensor
[-] - Hard to find in Canada

Microsoft Intellimouse 1.1

[+] - Have heard great things about the tracking
[+] - Looks very comfortable if your hands are the right size
[+] - Cheap
[-] - Have heard of people's hands getting cramped
[-] - Only one side button

Of course, I could go with the 518 again, but I'd rather not because, well, why buy the same thing when you could try something new? Trying something new can cost a lot, however, so I really need your help so I can choose wisely. :)